Soft resource signaling in relay networks

ABSTRACT

Disclosed are methods, systems, apparatus, and computer programs for determining in a new radio (NR) integrated access and backhaul (IAB) system a start symbol of available soft resources of an IAB node. In one aspect, a method includes determining, by a distributed unit (DU) of the IAB node and based on a configuration signal received from a central unit (CU) of an IAB donor, a configuration of available soft resources for a child link of the IAB node. The method further includes determining, based on the configuration of available soft resources, a start symbol of the available soft resources. The method also includes using the available soft resources for one or more child link transmissions starting from the start symbol.

CLAIM OF PRIORITY

This application claims priority to U.S. Provisional Patent Application No. 62/853,475 filed May 28, 2019, entitled “SOFT RESOURCE SIGNALING IN RELAY NETWORK,” the entirety of which is incorporated herein by reference.

BACKGROUND

User equipment (UE) can wirelessly communicate data using wireless communication networks. To wirelessly communicate data, the UE connects to a node of a radio access network (RAN) and synchronizes with the network.

SUMMARY

The present disclosure is directed towards methods, systems, apparatus, computer programs, or combinations thereof, for determining in a new radio (NR) integrated access and backhaul (IAB) system a start symbol of available soft resources of an IAB node.

In accordance with one aspect of the present disclosure, a method includes determining, by a distributed unit (DU) of an IAB node and based on a configuration signal received from a central unit (CU) of an IAB donor, a configuration of available soft resources for a child link of the IAB node; determining, based on the configuration of available soft resources, a start symbol of the available soft resources; and using the available soft resources for one or more child link transmissions starting from the start symbol.

Other versions include corresponding systems, apparatus, and computer programs to perform the actions of methods defined by instructions encoded on computer readable storage devices. These and other versions may optionally include one or more of the following features.

In some implementations, the configuration of available soft resources is applied relative to slot timing of the DU.

In some implementations, the configuration of available soft resources is indicated by the configuration signal on a symbol level per transmission direction if downlink and uplink timings of the DU are configured differently.

In some implementations, the start symbol is based on at least one of: a transmission direction of a last used symbol in the parent link, a resource type or transmission direction of soft resources in the child link, a downlink propagation delay (T_(D)) of the parent link, an uplink timing advance (T_(A)) of the parent link, or a downlink/uplink timing difference (T_(D/U)) at the DU.

In some implementations, a transmission direction of the parent link is downlink when the IAB node receives a transmission from a parent IAB node, a transmission direction of the parent link is uplink when the IAB node sends a transmission to the parent IAB node, a transmission direction of the child link is downlink when the IAB node sends a transmission to a child node, and a transmission direction of the child link is uplink when the IAB node receives a transmission from the child node.

In some implementations, a transmission direction of a last used symbol in the parent link and the available soft resources is downlink, the available soft resources overlap with the last used downlink symbol of the parent link, the last used downlink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+2.

In some implementations, a transmission direction of a last used symbol in the parent link is downlink, a transmission direction of the available soft resources is uplink, the available soft resources overlap with the last used downlink symbol of the parent link, a downlink/uplink timing difference (T_(D/U)) at the DU is greater than a downlink propagation delay (T_(D)) of the parent link, the last used downlink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+1.

In some implementations, a transmission direction of a last used symbol in the parent link is downlink, a transmission direction of the available soft resources is uplink, the available soft resources overlap with the last used downlink symbol of the parent link, a downlink/uplink timing difference (T_(D/U)) at the DU is less than a downlink propagation delay (T_(D)) of the parent link, the last used downlink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+2.

In some implementations, a transmission direction of a last used symbol in the parent link is uplink, a transmission direction of the available soft resources is downlink, the available soft resources overlap with the uplink symbol of the parent link, the last used downlink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+1.

In some implementations, a transmission direction of a last used symbol in the parent link and the available soft resources is uplink, a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is less than a symbol duration, the last used uplink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+1.

In some implementations, a transmission direction of a last used symbol in the parent link and the available soft resources is uplink, a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is greater than a symbol duration, the last used uplink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n.

In some implementations, the CU receives information indicative of guard symbols for the DU via an F1-AP interface message.

In accordance with another aspect of the present disclosure, a method includes determining a parameter indicating a number of guard symbols between a last used symbol of a parent link of an IAB node and a first available symbol in a child link of the IAB node; and transmitting the parameter to a central unit (CU) of an IAB donor.

Other versions include corresponding systems, apparatus, and computer programs to perform the actions of methods defined by instructions encoded on computer readable storage devices. These and other versions may optionally include one or more of the following features.

In accordance with yet another aspect of the present disclosure, a method includes determining, by an IAB donor, a parameter indicating a number of guard symbols between a last used symbol and a first available symbol for a distributed unit (DU) of an IAB node; and determining a configuration of available resources based on the number of guard symbols.

Other versions include corresponding systems, apparatus, and computer programs to perform the actions of methods defined by instructions encoded on computer readable storage devices. These and other versions may optionally include one or more of the following features.

In some implementations, the process further involves transmitting a configuration signal to the DU to indicate the configuration of available resources.

In some implementations, the process further involves receiving from the DU the parameter indicating the number of guard symbols.

In some implementations, the process further involves determining a start symbol of available soft resources; and including the start symbol of available soft resources in the configuration of available resources.

DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an example time-domain resource configuration for an Integrated Access and Backhaul (IAB) node, according to some implementations of the present disclosure.

FIGS. 2A, 2B, and 2C illustrate flowcharts of example processes, according to some implementations of the present disclosure.

FIG. 3 illustrates an example IAB architecture, according to some implementations of the present disclosure.

FIG. 4 illustrates an example architecture of a system of a network, according to some implementations of the present disclosure.

FIG. 5 illustrates an example architecture of a system including a first CN, according to some implementations of the present disclosure.

FIG. 6 illustrates an architecture of a system including a second CN, according to some implementations of the present disclosure.

FIG. 7 illustrates an example of infrastructure equipment, according to some implementations of the present disclosure.

FIG. 8 illustrates an example of a platform, according to some implementations of the present disclosure.

FIG. 9 illustrates various protocol functions that may be implemented in a wireless communication device, according to some implementations of the present disclosure.

FIG. 10 illustrates a block diagram illustrating components able to read instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies described herein, according to some implementations of the present disclosure.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

The present disclosure is related to Integrated Access and Backhaul (IAB) networks, which is a feature that enables multi-hop routing in cellular networks (e.g., as described in 3GPP Release 16). Generally, IAB networks include an IAB donor (e.g., a base station) that serves a plurality of IAB nodes operating as relays. Additionally, IAB networks implement a central unit-distributed unit (CU-DU) split. In this architecture, IAB nodes terminate the DU and the IAB donor terminates the CU. Further, each IAB node may include a mobile termination (MT) function. An IAB node may communicate with a parent IAB node and/or the IAB donor via the MT (e.g., using a parent link between the MT and the parent node/IAB donor). And the IAB node may communicate with user equipment (UEs) and/or MTs of child IAB nodes via the DU (e.g., using a child link between the DU and the UE or child IAB node). Signaling between MTs of IAB nodes and the CU of the IAB donor may use a Radio Resource Control (RRC) protocol. And signaling between DUs of IAB nodes and the CU of the IAB donor may use an F1-AP protocol. The architecture of IAB networks is explained in greater detail in FIG. 3 (discussed infra).

In IAB networks, time-domain resource allocation has the following properties. Generally, a time-domain resource (e.g., a symbol within a time slot) may be configured as a downlink (“DL” or “D”) resource, an uplink (“UL” or “U”) resource, or a flexible (F) resource. For instance, the time-domain resources may include a time division duplex (TDD) structure of slots or groups of slots in a radio frame. The configuration of a particular time-domain resource may specify a potential transmission direction of that resource (e.g., DL, UL, or F). From an MT perspective, a parent link may use D/U/F time-domain resources, and from a DU perspective, a child link may use D/U/F time-domain resources. Furthermore, the D/U/F time-domain resources of a DU (e.g., for a child link) may be configured as hard (H), soft (S), or not available (NA). These configurations indicate the resource availability of the configured D/U/F resources as unconditionally available (H), conditionally available (S), or unavailable (NA).

Furthermore, according to 3GPP, a parent IAB node has the ability to know a semi-static DU resource configuration of its child IAB nodes. If the full DU resource configuration information of a child node is not needed, then only the necessary configuration information is signaled to the parent IAB node. As such, an IAB CU (e.g., of an IAB donor) can configure the semi-static resource configuration for the parent IAB DU in a centralized manner. In particular, the resource configuration may include a DU D/U/F configuration and a DU H/S/NA configuration. In some examples, a soft resource can be used by the parent IAB node to make the resource available to the child node, irrespective of the outcome of any implicit determination of availability by the child node. As a result, the parent IAB node does not need to be aware of the outcome of an implicit determination of availability of DU soft resources at a child node.

In some examples, a DU H/S/NA configuration (also referred to as “resource availability”) is explicitly indicated per resource type (D/U/F) in each slot of the time-domain resources. However, in such examples, a misalignment in time of the DU and MT resources may occur. In order avoid this potential misalignment (e.g., when determining the validity of H/S/NA at the DU), three approaches are considered. In the first approach, H/S/NA is applied relative to the DU resource configuration slot timing without considering the MT resource configuration or timing. In the second approach, H/S/NA is applied relative to the MT resource configuration slot timing. In the third approach, H is applied relative to the DU resource configuration slot timing, S is implicitly determined by the DU based on whether the corresponding MT configuration indicates the MT resources is F (DU-S), and the remaining resources are assumed to be NA at the child DU.

Disclosed herein are methods and systems for applying H/S/NA relative to the DU resource configuration slot timing (i.e., the first approach). Among other things, the methods and systems define restrictions on the usage of a semi-static configuration (e.g., guard symbols) based on a deployment scenario or DL/UL switching times within an IAB node. Additionally, the methods and systems enable a CU of an IAB donor to obtain information about the guard symbols for a given DU configuration (if needed). These methods and systems achieve a flexible resource availability configuration to coordinate time resources between an MT and a DU of an IAB node, which is an improvement over existing and conventional solutions.

In an embodiment, resource availability is explicitly configured per resource type based on transmission direction in each slot with respect to DU slot timing. As such, the granularity of resource availability configuration is either on the level of resource type if multiple resource types are configured within a slot, or on the level of a slot. To avoid potential misalignment in time of the configured DU and MT resources, when signaling the available soft resources to the DU, the CU may indicate the available resources on a symbol level per transmission direction if the DU DL and UL timings are configured differently, thereby enabling switching time for a child link. Additionally, in order to maximize the soft resource allocation, the CU may indicate a start symbol of the available soft resources. In an example, the start symbol is based on at least one of a transmission direction of a last used symbol in the parent link and an overlapping soft resource, a downlink propagation delay, an uplink timing advance, or a DU internal DL/UL timing difference.

In some examples, the CU may also determine the start symbol based on a number of soft resource guard symbols. Accordingly, another embodiment involves the DU signaling to the CU information indicative of the number of soft resource guard symbols. In this embodiment, the CU may receive the information for a given DU via an F1-AP interface management signaling message. In an example, an informational element (IE)transmitted in SIB1 is enhanced to include parameters signaling the number of guard symbols.

Determining and Signaling Maximum Available Soft Resources for a DU

In an embodiment, resource availability (e.g., H/S/NA) is explicitly configured (e.g., by the CU) per resource type based on transmission direction (e.g., D/U/F) in each slot with respect to DU slot timing. As a result, the granularity of the resource availability configuration is either on a slot level or, if multiple resource types are configured within a slot, on a resource type level. To avoid potential misalignment in time of the configured DU and MT resources, when signaling the available soft resources to the DU, available resources are indicated on a symbol level per transmission direction. Doing so enables switching time for a child link if the DU DL/UL timings are configured differently. However, when signaling the resource availability as such, there may be additional restrictions on the usage of the semi-static configuration (e.g. guard symbols) based on deployment scenario or DL/UL switching times within an IAB node. These additional restrictions can be illustrated using FIG. 1.

FIG. 1 illustrates an example time-domain resource configuration 100 for an IAB node, according to some implementations. In this example, it is assumed that the IAB node has an established parent link with a parent IAB node (or an IAB donor) and an established child link with a child IAB node. The time-domain resource configuration 100 includes two sets of time-domain resources 110, 120 for the IAB node. The first set 110 includes resources located in symbol indices n, n+1, and n+2. The second set 120, which occurs later in time than the first set, includes resources located in symbol indices k, k+1, and k+2. These resources may be used by the MT for the parent link or by the DU for the child link. In FIG. 1, two example child links cases are illustrated. In case-1, the child link is configured for DL transmission, and in case-2, the child link is configured for UL transmission.

Starting with the first set of resources 110, a DL transmission is scheduled at symbol n of the parent link. As such, a DL RX of the MT of the IAB node may receive a transmission from a DL TX of a parent DU at symbol n. Due to propagation delay, the MT receives the DL symbol n after a time delay T_(D). As also shown in FIG. 1, because the symbol n is used by the parent link, the symbol is designated as a used resource in the parent link. As also shown in FIG. 1, the parent link does not use the symbols located in symbol indices n+1 and n+2. As a result, child link resources that correspond to the unused parent link resources are available soft resources that the DU can use to schedule child link traffic. However, depending on several factors, the available resources can have different offsets with respect to the last used symbol in the parent link.

As an example, in case-1 where the child link is configured for DL transmission, the available soft DL resource start from symbol n+2. This is because the n symbol of the parent link overlaps with symbols n and n+1 in the child link. Thus, because symbols n and n+1 cannot be used by the DU, the symbols are designated as “Soft NA” resources. On the other hand, because symbol n+2 can be used by the DU, the symbol is designated as a “Soft Available” resource. As another example, in case-2 where the child link is configured for UL transmission, the first available soft UL resource is found in symbol index n+1 of the child link. In this example, due to a DL/UL switching time T_(D/U), the n symbol of the parent link only overlaps with symbol n of the child link. Thus, in case-2, only symbol n is designated as “Soft NA,” and symbols n+1 and n+2 are designated as “Soft Available.”

Turning to the second set of resources 120, a UL transmission is scheduled at symbol k of the parent link. Thus, an UL RX of the parent DU may receive a transmission from an UL TX of the MT. As shown in FIG. 1, the resources of the parent link may include resources at symbol indices k, k+1, and k+2. Due to a required timing advance, the MT transmits the UL symbol k with a time advance T_(A). Here, the subsequent symbols k+1 and k+2 are not used by parent link, and thus, the corresponding resources are available as soft resources for the DU to schedule child link traffic. As shown in FIG. 1, in both case-1 and case-2, only symbol k of the child link overlaps with symbol k of the parent link. Thus, only symbol k of the child link is designated as “Soft NA,” and symbols k+1 and k+2 are designated as “Soft Available.”

These examples of FIG. 1 illustrate that a first or start available soft symbol for a DU may vary depending on the DU configuration (among other factors). In an embodiment, in order to maximize the utilization of soft resources, the first start available soft symbol may be determined and signaled by the CU. In particular, the CU may generate a configuration signal that is indicative of the configuration of available resources, perhaps on a symbol level per transmission direction. This configuration signal may also be indicative of the first available soft resource for the DU.

In an embodiment, the first available soft resource may be determined based on one or more factors. More specifically, and as illustrated by FIG. 1, when the CU explicitly indicates the available soft resources to an DU of an IAB node (e.g., on a symbol level per transmission direction), the first or start available soft symbol depends on one or more of the following factors: (i) a transmission direction of a last used symbol in a parent link of the IAB node; (ii) a resource type or transmission direction of soft resources in a child link of the IAB node; (iii) a DL propagation delay T_(D) of the parent link; (iv) an UL timing advance T_(A) of the parent link; or (v) a timing difference T_(D/U) of DL/UL at the DU (e.g., DL/UL switching time). Based on one or more of these factors, the following options are derived and applied to corresponding scenarios of DU/MT resource configurations.

In a first scenario, a transmission direction of the parent link and the child link is downlink, and one or more DL soft resources of the child link overlap one or more DL resources of the parent link. In this scenario, if the last used DL symbol of the parent link is at symbol index n, then it is determined that the first available DL soft symbol in the child link starts from symbol index n+2. This scenario corresponds to case-1 in the first set of resources 110 in FIG. 1.

In a second scenario, a transmission direction of the parent link is downlink and a transmission direction of the child link is uplink. Further, one or more UL soft resources of the child link overlap one or more DL resources of the parent link, and the DU DL/UL timing difference T_(D/U) is greater than a DL propagation delay T_(D). In this scenario, if the last used DL symbol of the parent link is at symbol index n, then it is determined that the first available UL soft symbol in the child link starts from symbol index n+1. This scenario corresponds to case-2 in the first set of resources 110 in FIG. 1.

In a third scenario, a transmission direction of the parent link is downlink and a transmission direction of the child link is uplink. Further, one or more UL soft resources of the child link overlap one or more DL resources of the parent link, and the DU DL/UL timing difference T_(D/U) is less than a DL propagation delay T_(D). In this scenario, if the last used DL symbol of the parent link is at symbol index n, then it is determined that the first available UL soft symbol in the child link starts from symbol index n+2.

In a fourth scenario, a transmission direction of a last used symbol in the parent link is uplink and a transmission direction of the child link is downlink. Further, one or more DL soft resources of the child link overlap one or more UL resources of the parent link. In this scenario, if the last used UL symbol of the parent link is at symbol index n, then it is determined that the first available DL soft symbol in the child link starts from symbol index n+1. This scenario corresponds to case-1 in the second set of resources 120 in FIG. 1.

In a fifth scenario, a transmission direction of the parent link and the child link is uplink. Further, one or more UL soft resources of the child link overlap one or more UL resources of parent link, and the sum of the DU DL/UL timing difference T_(D/U) and the UL timing advance T_(A) of the parent link is less than a symbol duration. In this scenario, if the last used UL symbol of the parent link is at symbol index n, then it is determined that the first available UL soft symbol in the child link starts from symbol index n+1. This scenario corresponds to case-2 in the second set of resources 120 in FIG. 1.

In a sixth scenario, a transmission direction of the parent link and the child link is uplink. Further, the sum of the DU DL/UL timing difference T_(D/U) and the UL timing advance T_(A) of the parent link is greater than a symbol duration. In this scenario, if the last used UL symbol of the parent link is at symbol index n, then the first available UL soft symbol in the child link starts from symbol index n.

F1-AP Based DU Signaling of Soft Resource Guard Symbols

In an embodiment, in order for the CU to correctly signal the proper start of soft available resources, the CU may determine a number of guard symbols between a last used symbol in the parent link of the DU and the first available soft resources for the child link. In an example, the DU may determine the number of guard symbols and may signal an indication of the number of guard symbols to the CU.

In an embodiment, an F1-AP based method is used by the DU for signaling the indication of the number of guard symbols. In this method, the CU can receive information about the required guard symbols for a given DU via an F1-AP interface management signaling message. In an example, the message is GNB-DU-CONFIGURATION-UPDATE. In this example, an informational element, such as TDD-UL-DL-ConfigCommon, that is transmitted in SIB1 is enhanced to include parameters that signal the number of guard symbols. Within examples, the parameters may correspond to the six scenarios described above. For the first and fourth scenarios, the number of symbol index offsets between the first available DL soft symbol and the last used DL or UL symbol in the parent link are fixed to 2 and 1, respectively. As such, in an example, if a transmission direction of the parent link is downlink, then the DU does not signal the number of symbol index offsets since they are fixed. However, the DU may signal the number of symbol offsets between the first available UL soft symbol and the last used DL/UL symbol in the parent link (e.g., the second, third, fifth, and sixth scenarios described above).

In an example, the information element TDD-UL-DL-ConfigCommon may include one or both of two fields: symbOffsetFromDLUsedSymbToULSoftSymb and symbOffsetFromULUsedSymbToULSoftSymb. The first field defines the symbol offset between the last used DL symbol in the parent link and the first available UL soft symbol. Depending on whether the second or third scenario described above occurs, this parameter is set as either 1 or 2. For instance, the second scenario may be signaled as 1 and the third scenario may be signaled as 2, or vice versa. The second field defines the symbol offset between the last used UL symbol in the parent link and the first available UL soft symbol. Depending on whether the fifth or sixth scenario described above occurs, this parameter shall be set as either 0 or 1. For instance, the fifth scenario may be signaled as 0 and the sixth scenario may be signaled as 1, or vice versa.

FIGS. 2A, 2B, and 2C illustrate flowcharts of example processes 200, 220, and 240, according to some implementations. For clarity of presentation, the description that follows generally describes the processes in the context of the other figures in this description. For example, the processes can be performed by an IAB node or an entity thereof (e.g., as shown in FIG. 3). However, it will be understood that the processes may be performed, for example, by any suitable system, environment, software, and hardware, or a combination of systems, environments, software, and hardware, as appropriate. In some implementations, various steps of the processes can be run in parallel, in combination, in loops, or in any order.

FIG. 2A is a flowchart of an example process 200 for determining a start symbol of available soft resources of an IAB node of an IAB system, where the IAB node includes a distributed unit (DU) and a mobile termination (MT), and where the IAB node has a parent link and a child link. At step 202, the process involves determining, by a distributed unit (DU) of an IAB node and based on a configuration signal received from a central unit (CU) of an IAB donor, a configuration of available soft resources for a child link of the IAB node. At step 204, the process involves determining, based on the configuration of available soft resources, a start symbol of the available soft resources. At step 206, the process involves using the available soft resources for one or more child link transmissions starting from the start symbol.

In some implementations, the configuration of available soft resources is applied relative to slot timing of the DU.

In some implementations, the configuration of available soft resources is indicated by the configuration signal on a symbol level per transmission direction if downlink and uplink timings of the DU are configured differently.

In some implementations, the start symbol is based on at least one of: a transmission direction of a last used symbol in the parent link, a resource type or transmission direction of soft resources in the child link, a downlink propagation delay (T_(D)) of the parent link, an uplink timing advance (T_(A)) of the parent link, or a downlink/uplink timing difference (T_(D/U)) at the DU.

In some implementations, a transmission direction of the parent link is downlink when the IAB node receives a transmission from a parent IAB node, a transmission direction of the parent link is uplink when the IAB node sends a transmission to the parent IAB node, a transmission direction of the child link is downlink when the IAB node sends a transmission to a child node, and a transmission direction of the child link is uplink when the IAB node receives a transmission from the child node

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link and the available soft resources is downlink; determining that the available soft resources overlap with the last used downlink symbol of the parent link; determining that the last used downlink symbol of the parent link is at symbol index n, and responsively determining that the start symbol of the available soft resources is at symbol index n+2. Thus, in some implementations, a transmission direction of a last used symbol in the parent link and the available soft resources is downlink, the available soft resources overlap with the last used downlink symbol of the parent link, the last used downlink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+2.

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link is downlink; determining that a transmission direction of the available soft resources is uplink; determining that the available soft resources overlap with the last used downlink symbol of the parent link; determining that a downlink/uplink timing difference (T_(D/U)) at the DU is greater than a downlink propagation delay (T_(D)) of the parent link, determining that the last used downlink symbol of the parent link is at symbol index n, and responsively determining that the start symbol of the available soft resources is at symbol index n+1. Thus, in some implementations, a transmission direction of a last used symbol in the parent link is downlink, a transmission direction of the available soft resources is uplink, the available soft resources overlap with the last used downlink symbol of the parent link, a downlink/uplink timing difference (T_(D/U)) at the DU is greater than a downlink propagation delay (T_(D)) of the parent link, the last used downlink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+1.

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link is downlink; determining that a transmission direction of the available soft resources is uplink; determining that the available soft resources overlap with the last used downlink symbol of the parent link; determining that a downlink/uplink timing difference (T_(D/U)) at the DU is less than a downlink propagation delay (T_(D)) of the parent link; determining that the last used downlink symbol of the parent link is at symbol index n; and responsively determining that the start symbol of the available soft resources is at symbol index n+2. Thus, in some implementations, a transmission direction of a last used symbol in the parent link is downlink, a transmission direction of the available soft resources is uplink, the available soft resources overlap with the last used downlink symbol of the parent link, a downlink/uplink timing difference (T_(D/U)) at the DU is less than a downlink propagation delay (T_(D)) of the parent link, the last used downlink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+2.

In some implementations, the process further involves: determining that transmission direction of a last used symbol in the parent link is uplink; determining that a transmission direction of the available soft resources is downlink: determining that the available soft resources overlap with the uplink symbol of the parent link; determining that the last used downlink symbol of the parent link is at symbol index n; and responsively determining that the start symbol of the available soft resources is at symbol index n+1. As such, in some implementations, a transmission direction of a last used symbol in the parent link is uplink, a transmission direction of the available soft resources is downlink, the available soft resources overlap with the uplink symbol of the parent link, the last used downlink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+1.

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link and the available soft resources is uplink; determining that a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is less than a symbol duration; determining that the last used uplink symbol of the parent link is at symbol index n; and responsively determining that the start symbol of the available soft resources is at symbol index n+1. As such, in some implementations, a transmission direction of a last used symbol in the parent link and the available soft resources is uplink, a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is less than a symbol duration, the last used uplink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n+1.

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link and the available soft resources is uplink; determining that a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is greater than a symbol duration; determining that the last used uplink symbol of the parent link is at symbol index n; and responsively determining that the start symbol of the available soft resources is at symbol index n. As such, in some implementations, a transmission direction of a last used symbol in the parent link and the available soft resources is uplink, a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is greater than a symbol duration, the last used uplink symbol of the parent link is at symbol index n, and the start symbol of the available soft resources is at symbol index n.

In some implementations, the CU receives information indicative of guard symbols for the DU via an F1-AP interface message.

FIG. 2B is a flowchart of an example process 220 for determining a number of guard symbols in a child link of an IAB node, where the IAB node includes a distributed unit (DU) and a mobile termination (MT), and where the IAB node also has a parent link. At step 222, the process involves determining a parameter indicating a number of guard symbols between a last used symbol of a parent link of an IAB node and a first available symbol in a child link of the IAB node. At step 224, the process involves transmitting the parameter to a central unit (CU) of an IAB donor.

In some implementations, the number of guard symbols is based on at least one of: a transmission direction of a last used symbol in the parent link, a resource type or transmission direction of soft resources in the child link, a downlink propagation delay (T_(D)) of the parent link, an uplink timing advance (T_(A)) of the parent link, or a downlink/uplink timing difference (T_(D/U)) at the DU.

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link and the available soft resources is downlink; determining that the available soft resources overlap with the last used downlink symbol of the parent link; determining that the last used downlink symbol of the parent link is at symbol index n; determining that the start symbol of the available soft resources is at symbol index n+2; and responsively determining that the number of guard symbols is 2.

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link is downlink; determining that a transmission direction of the available soft resources is uplink; determining that the available soft resources overlap with the last used downlink symbol of the parent link; determining that a downlink/uplink timing difference (T_(D/U)) at the DU is greater than a downlink propagation delay (T_(D)) of the parent link; determining that the last used downlink symbol of the parent link is at symbol index n; determining that the start symbol of the available soft resources is at symbol index n+1; and responsively determining that the number of guard symbols is 1.

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link is downlink; determining that a transmission direction of the available soft resources is uplink; determining that the available soft resources overlap with the last used downlink symbol of the parent link; determining that a downlink/uplink timing difference (T_(D/U)) at the DU is less than a downlink propagation delay (T_(D)) of the parent link; determining that the last used downlink symbol of the parent link is at symbol index n; determining that the start symbol of the available soft resources is at symbol index n+2; and responsively determining that the number of guard symbols is 2.

In some implementations, the process further involves: determining that transmission direction of a last used symbol in the parent link is uplink; determining that a transmission direction of the available soft resources is downlink; determining that the available soft resources overlap with the uplink symbol of the parent link; determining that the last used downlink symbol of the parent link is at symbol index n; determining that the start symbol of the available soft resources is at symbol index n+1; and responsively determining that the number of guard symbols is 1.

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link and the available soft resources is uplink; determining that a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is less than a symbol duration; determining that the last used uplink symbol of the parent link is at symbol index n, determining that the start symbol of the available soft resources is at symbol index n+1; and responsively determining that the number of guard symbols is 2.

In some implementations, the process further involves: determining that a transmission direction of a last used symbol in the parent link and the available soft resources is uplink; determining that a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is greater than a symbol duration; determining that the last used uplink symbol of the parent link is at symbol index n; determining that the start symbol of the available soft resources is at symbol index n; and responsively determining that the number of guard symbols is 0.

FIG. 2C is a flowchart of an example process 240 for determining a configuration of available resources for a child link of an IAB node, where the IAB node includes a distributed unit (DU) and a mobile termination (MT), and where the IAB node also has a parent link. At step 242, the process determining, by an IAB donor, a parameter indicating a number of guard symbols between a last used symbol and a first available symbol for a distributed unit (DU) of an IAB node. At step 244, the process involves determining a configuration of available resources based on the number of guard symbols.

In some implementations, the process further involves transmitting a configuration signal to the DU to indicate the configuration of available resources.

In some implementations, the process further involves receiving from the DU the parameter indicating the number of guard symbols.

In some implementations, the process further involves determining a start symbol of available soft resources; and including the start symbol of available soft resources in the configuration of available resources.

The example processes shown in FIGS. 2A, 2B, and 2C can be modified or reconfigured to include additional, fewer, or different steps (not shown in the figures), which can be performed in the order shown or in a different order.

FIG. 3 illustrates an example Integrated Access and Backhaul (IAB) architecture in accordance with various embodiments. In particular, FIG. 3 illustrates IAB architecture in standalone (SA) mode. The IAB architecture of FIG. 3 may use the same infrastructure and spectral resources for both access and backhaul communications. FIG. 3 shows a reference diagram for IAB in standalone mode, which contains one IAB donor 304 (also referred to as an “anchor node” or the like) and multiple IAB nodes, such as IAB-nodes 306 a, 306 b (also referred to as IAB relay nodes (RNs), relay Transmission/Reception Points (rTRPs), or the like). The IAB donor 304 is treated as a single logical node that comprises a set of functions such as gNB-DU 308 a, gNB-CU-CP 308 b, gNB-CU-UP 308 c, and potentially other functions. In some implementations, the IAB donor 304 can be split according to the aforementioned functions, which can all be either collocated or non-collocated as allowed by 3GPP NG-RAN architecture. Some of the functions presently associated with the IAB donor 304 may be moved outside of the IAB donor.

In FIG. 3, various UEs (e.g., UE 310, UEs 401, 501, and 601 in FIGS. 4, 5, and 6 discussed infra) access IAB nodes. An IAB node is a network node in an IAB deployment having UE and (at least part of) gNB functions. As shown by FIG. 3, some IAB nodes access other IAB nodes, and some IAB nodes access an IAB donor. An IAB donor is a network node in an IAB deployment that terminates NG interfaces via wired connection(s). The IAB donor is a RAN node that provides a UE's interface to a core network 302 (e.g., the 5GC in FIG. 3 and CN 620 in FIG. 6 discussed infra) and wireless backhauling functionality to IAB nodes. An IAB node is a relay node and/or a RAN node that supports wireless access to UEs (e.g., via wireless access link 314) and wirelessly backhaul access traffic.

IAB strives to reuse existing functions and interfaces defined for access. In particular, Mobile-Termination (MT), gNB-DU, gNB-CU, UPF, AMF and SMF as well as the corresponding interfaces NR Uu (between MT and gNB), F1, NG, X2 and N4 are used as baseline for the IAB architectures. Modifications or enhancements to these functions and interfaces for the support of IAB will be explained in the context of the architecture discussion. The Mobile-Termination (MT) function, such as 320, has been defined a component of the Mobile Equipment. In the context of IAB, MT is referred to as a function residing on an IAB node that terminates the radio interface layers of the backhaul Uu interface toward the IAB donor or other IAB nodes. Additional functionality, such as multi-hop forwarding, is included in the architecture.

IAB nodes can operate in SA or in NSA mode. When operating in NSA, the IAB node only uses the NR link for backhauling. The UE (e.g., UE 401 of FIG. 4) connecting to an IAB node may choose a different operation mode than the IAB node. The UE may further connect to a different type of core network than the IAB node it is connected to. In this case, Decor or slicing can be used for CN selection. IAB nodes operating in NSA mode may be connected to the same or to different eNBs. UEs that also operate in NSA-node may connect to the same or to a different RAN node (e.g., RAN node 411 of FIG. 4) than the IAB node to which they are connected.

Examples for operation in SA and NSA mode include: (1) the UEs and IAB nodes operate in SA with NGC; (2) UEs operate in NSA with EPC while IAB nodes operates in SA with NGC; and (3) UEs and IAB nodes operate in NSA with EPC. For the third example, the UEs and IAB nodes operate in NSA with EPC (or 5GC for NR implementations), and the IAB node may use the LTE leg (or NR leg for NR implementations) for IAB node initial access and configuration, topology management, route selection, and resource partitioning.

In embodiments where multi-hop and topology adaptation are supported, the IAB nodes include topology management mechanisms and route selection and optimization (RSO) mechanisms. Topology management mechanisms include protocol stacks, interfaces between rTRPs or IAB nodes, control and user plane procedures for identifying one or more hops in the IAB network, forwarding traffic via one or multiple wireless backhaul links (e.g., wireless backhaul 312) in the IAB network, handling of QoS, and the like. The RSO mechanisms include mechanisms for discovery and management of backhaul links for TRPs with integrated backhaul and access functionalities; RAN-based mechanisms to support dynamic route selection (potentially without core network involvement) to accommodate short-term blocking and transmission of latency-sensitive traffic across backhaul links; and mechanisms for evaluating different resource allocations/routes across multiple nodes for end-to-end RSO.

The operation of the different links may be on the same frequencies (“in-band”) or different frequencies (“out-of-band”). In-band backhauling includes scenarios where access and backhaul links at least partially overlap in frequency creating half-duplexing or interference constraints, which may imply that an IAB node may not transmit and receive simultaneously on both links. By contrast, out-of-band scenarios may not have such constraints. In embodiments, one or more of the IAB nodes include mechanisms for dynamically allocating resources between backhaul and access links, which include mechanisms to efficiently multiplex access and backhaul links (for both DL and UL directions) in time, frequency, or space under a per-link half-duplex constraint across one or multiple backhaul link hops for both TDD and FDD operation; and cross-link interference (CLI) measurement, coordination and mitigation between rTRPs and UEs.

Architecture Groups and Types

There are five different types of IAB architectures that are divided into two architecture groups. Architecture group 1 comprises architectures 1 a and 1 b, which include CU/DU split architectures. Architecture 1 a includes backhauling of F1-U uses an adaptation layer or GTP-U combined with an adaptation layer, and hop-by-hop forwarding across intermediate nodes uses the adaptation layer for operation with NGC or PDN-connection-layer routing for operation with EPC. Architecture 1 b includes backhauling of F1-U on access node uses GTP-U/UDP/IP, and hop-by-hop forwarding across intermediate node uses the adaptation layer.

Architecture group 2 comprises architectures 2 a, 2 b and 2 c. Architecture 2 a includes backhauling of F1-U or NG-U on access node uses GTP-U/UDP/IP, and hop-by-hop forwarding across intermediate node uses PDU-session-layer routing. Architecture 2 b includes backhauling of F1-U or NG-U on access node uses GTP-U/UDP/IP, and hop-by-hop forwarding across intermediate node uses GTP-U/UDP/IP nested tunneling. Architecture 2 c includes backhauling of F1-U or NG-U on access node uses GTP-U/UDP/IP, and hop-by-hop forwarding across intermediate node uses GTP-U/UDP/IP/PDCP nested tunneling.

Architecture Group 1

Architecture 1 a leverages CU/DU-split architecture. In this architecture, each IAB node holds a DU (e.g., DU 322) and an MT (e.g., MT 320). Via the MT, the IAB node connects to an upstream IAB node or the IAB donor. Via the DU, the IAB node establishes RLC-channels to UEs and to MTs of downstream IAB nodes. For MTs, this RLC-channel may refer to a modified RLC*. An IAB node can connect to more than one upstream IAB node or IAB donor DU. The IAB node may contain multiple DUs, but each DU part of the IAB node has F1-C connection only with one IAB donor CU-CP.

The donor also holds a DU to support UEs and MTs of downstream IAB nodes. The IAB donor holds a CU for the DUs of all IAB nodes and for its own DU. It is FFS if different CUs can serve the DUs of the IAB nodes. Each DU on an IAB node connects to the CU in the IAB donor using a modified form of F1, which is referred to as F1*. F1*-U runs over RLC channels on the wireless backhaul between the MT on the serving IAB node and the DU on the donor. F1*-U transport between MT and DU on the serving IAB node as well as between DU and CU on the donor is FFS. An adaptation layer is added, which holds routing information, enabling hop-by-hop forwarding. It replaces the IP functionality of the standard F1-stack. F1*-U may carry a GTP-U header for the end-to-end association between CU and DU. In a further enhancement, information carried inside the GTP-U header may be included into the adaption layer. Further, optimizations to RLC may be considered such as applying ARQ only on the end-to-end connection opposed to hop-by-hop. The F1*-U protocol stacks for this architecture include enhancements of RLC (referred to as RLC*). The MT of each IAB node further sustains NAS connectivity to the NGC (e.g., for authentication of the IAB node, and sustains a PDU-session via the NGC (e.g., to provide the IAB node with connectivity to the OAM.

For NSA operation with EPC, the MT is dual-connected with the network using EN-DC. The IAB node's MT sustains a PDN connection with the EPC (e.g., to provide the IAB node with connectivity to the OAM.

Architecture 1 b also leverages CU/DU-split architecture. In this architecture, the IAB donor only holds one logical CU. An IAB node can connect to more than one upstream IAB node or IAB donor DU. The IAB node may contain multiple DUs, but each DU part of the IAB node has F1-C connection only with one IAB donor CU-CP.

In this architecture, each IAB node and the IAB donor hold the same functions as in architecture 1 a. Also, as in architecture 1 a, every backhaul link establishes an RLC-channel, and an adaptation layer is inserted to enable hop-by-hop forwarding of F1*.

Opposed to architecture 1 a, the MT on each IAB node establishes a PDU-session with a UPF residing on the donor. The MT's PDU-session carries F1* for the collocated DU. In this manner, the PDU-session provides a point-to-point link between CU and DU. On intermediate hops, the PDCP-PDUs of F1* are forwarded via adaptation layer in the same manner as described for architecture 1 a.

For NSA operation with EPC, the MT is dual-connected with the network using EN-DC. In this case, the IAB node's MT sustains a PDN connection with an L-GW residing on the donor.

Adaptation Layer: As mentioned previously, an adaptation layer is inserted to enable hop-by-hop forwarding of F1*. In these embodiments, the UE establishes RLC channels to the DU on the UE's access IAB-node in compliance with 3GPP TS 38.300. Each of these RLC-channels is extended via a potentially modified form of F1-U, referred to as F1*-U, between the UE's access DU and the IAB-donor. The information embedded in F1*-U is carried over RLC-channels across the backhaul links. Transport of F1*-U over the wireless backhaul is enabled by an adaptation layer, which is integrated with the RLC channel. Within the IAB-donor (referred to as fronthaul), the baseline is to use native F1-U stack (see section 9 of 3GPP TR 38.874). The IAB-donor DU relays between F1-U on the fronthaul and F1*-U on the wireless backhaul.

In architecture 1 a, information carried on the adaptation layer supports the following functions: identification of the UE-bearer for the PDU; routing across the wireless backhaul topology; QoS-enforcement by the scheduler on DL and UL on the wireless backhaul link; mapping of UE user-plane PDUs to backhaul RLC channels; and other suitable functions.

In architecture 1 b, information carried on the adaptation layer supports the following functions: routing across the wireless backhaul topology; QoS-enforcement by the scheduler on DL and UL on the wireless backhaul link; mapping of UE user-plane PDUs to backhaul RLC channels; and other suitable functions

In case the IAB-node is connected via multiple paths, different identifiers (e.g., UE-bearer-specific Id; UE-specific Id; route Id, IAB-node or IAB-donor address; QoS information, etc.) in the adaptation layer will be associated with the different paths, enabling adaptation layer routing on the different paths. The different paths can be associated with different backhaul RLC-channels.

Content carried on the adaptation layer header may include, for example, UE-bearer-specific Id; UE-specific Id; route Id, IAB-node or IAB-donor address; QoS information; and/or other like information. IAB-nodes use the identifiers carried via Adapt to ensure required QoS treatment and to decide which hop a packet should be sent to. The UE-bearer-specific Id may be used by the IAB-node and the IAB-donor to identify the PDU's UE-bearer. UE's access IAB-node would then map Adapt information (e.g. UE-specific ID, UE-bearer specific ID) into the corresponding C-RNTI and LCID. The IAB-donor DU may also need to map Adapt information into the F1-U GTP-U TEID used between Donor DU and Donor CU. UE-bearer-specific Id, UE-specific Id, Route Id, or IAB-node/IAB-donor address may be used (in combination or individually) to route the PDU across the wireless backhaul topology. UE-bearer-specific Id, UE-specific Id, UE's access node IAB ID, or QoS information may be used (in combination or individually) on each hop to identify the PDU's QoS treatment. The PDU's QoS treatment may also be based on the LCID.

In some embodiments, the adaptation layer may include one or more sublayers, and therefore, the adaptation header may have different structures in different embodiments. For example, the GTP-U header may become a part of the adaptation layer. It is also possible that the GTP-U header is carried on top of the adaptation layer to carry end-to-end association between the IAB-node DU and the CU. Alternatively, an IP header may be part of the adaptation layer or carried on top of the adaptation layer. In one example, the IAB-donor DU holds an IP routing function to extend the IP-routing plane of the fronthaul to the IP-layer carried by adapt on the wireless backhaul. This allows native F1-U to be established e2e (e.g., between IAB-node DUs and IAB-donor CU-UP). The scenario implies that each IAB-node holds an IP-address, which is routable from the fronthaul via the IAB-donor DU. The IAB-nodes' IP addresses may further be used for routing on the wireless backhaul. Note that the IP-layer on top of Adapt does not represent a PDU session. The MT's first hop router on this IP-layer therefore does not have to hold a UPF.

Architecture Group 2

In architecture 2 a, UEs and IAB nodes use SA-mode with NGC. In this architecture, the IAB node holds an MT to establish an NR Uu link with a gNB on the parent IAB node or IAB donor. Via this NR-Uu link, the MT sustains a PDU-session with a UPF that is collocated with the gNB. In this manner, an independent PDU-session is created on every backhaul link. Each IAB node further supports a routing function to forward data between PDU-sessions of adjacent links. This creates a forwarding plane across the wireless backhaul. Based on PDU-session type, this forwarding plane supports IP or Ethernet. In case PDU-session type is Ethernet, an IP layer can be established on top. In this manner, each IAB node obtains IP-connectivity to the wireline backhaul network. An IAB node can connect to more than one upstream IAB node or IAB donor.

All IP-based interfaces such as NG, Xn, F1, N4, etc. are carried over this forwarding plane. In the case of F1, the UE-serving IAB node would contain a DU for access links in addition to the gNB and UPF for the backhaul links. The CU for access links would reside in or beyond the IAB Donor. The NG-U protocol stack for IP-based and for Ethernet-based PDU-session type may be used for this architecture.

In case the IAB node holds a DU for UE-access, it may not be required to support PDCP-based protection on each hop since the end user data will already be protected using end to end PDCP between the UE and the CU. Details are FFS.

For NSA operation with EPC, the MT is dual-connected with the network using EN-DC. In this case, the IAB node's MT sustains a PDN-connection with an L-GW residing on the parent IAB node or the IAB donor. All IP-based interfaces such as S1, S5, X2, etc. are carried over this forwarding plane.

In architecture 2 b, the IAB node holds an MT to establish an NR Uu link with a gNB on the parent IAB node or IAB donor. Via this NR-Uu link, the MT sustains a PDU-session with a UPF. Opposed to architecture 2 a, this UPF is located at the IAB donor. Also, forwarding of PDUs across upstream IAB nodes is accomplished via tunneling. The forwarding across multiple hops therefore creates a stack of nested tunnels. As in architecture 2 a, each IAB node obtains IP-connectivity to the wireline backhaul network. All IP-based interfaces such as NG, Xn, F1, N4, etc. are carried over this forwarding IP plane. An IAB node can connect to more than one upstream IAB node or IAB donor.

For NSA operation with EPC, the MT is dual-connected with the network using EN-DC. In this case, the IAB node's MT sustains a PDN-connection with an L-GW residing on the IAB donor.

Architecture 2 c leverages DU-CU split. The IAB node holds an MT that sustains an RLC-channel with a DU on the parent IAB node or IAB donor. The IAB donor holds a CU and a UPF for each IAB node's DU. The MT on each IAB node sustains a NR-Uu link with a CU and a PDU session with a UPF on the donor. Forwarding on intermediate nodes is accomplished via tunneling. The forwarding across multiple hops creates a stack of nested tunnels. As in architecture 2 a and 2 b, each IAB node obtains IP-connectivity to the wireline backhaul network. Opposed to architecture 2 b, however, each tunnel includes an SDAP/PDCP layer. All IP-based interfaces such as NG, Xn, F1, N4, etc. are carried over this forwarding plane. An IAB node can connect to more than one upstream IAB node or IAB donor.

For NSA operation with EPC, the MT is dual-connected with the network using EN-DC. In this case, the IAB node's MT sustains a PDN-connection with an L-GW residing on the IAB donor.

Multi-Hop Backhauling

In embodiments, the IAB system architecture supports multi-hoping backhauling. IAB multi-hop backhauling provides more range extension than single hopping systems. Multi-hop backhauling further enables backhauling around obstacles (e.g., buildings in urban environment for in-clutter deployments). The maximum number of hops in a deployment may depend on many factors such as frequency, cell density, propagation environment, traffic load, various KPIs, and/or other like factors. Additionally, the weights assigned to each of these factors may change dynamically over time. With increasing number of hops, scalability issues may arise and limit performance or increase signaling load to unacceptable levels; therefore, scalability to hop-count may be considered as an important KPI for planning and deployment (e.g., SON) purposes. In some implementations, there may be no limits on the number of backhaul hops

Topology Adaptation

The IAB system architecture also supports topology adaptation. Topology adaptation refers to procedures that autonomously reconfigure the backhaul network under circumstances, such as blockage or local congestion without discontinuing services for UEs and/or to mitigate service disruption for UEs. For example, wireless backhaul links may be vulnerable to blockage due to moving objects such as vehicles, weather-related events (e.g., seasonal changes (foliage)), infrastructure changes (e.g., new buildings), and/or the like. These vulnerabilities may apply to physically stationary IAB nodes and/or mobile IAB nodes. Also, traffic variations can create uneven load distribution on wireless backhaul links leading to local link or node congestion. In various implementations, topology adaptation for physically fixed IAB nodes is supported to enable robust operation to mitigate blockage and load variation on backhaul links.

Physical Layer Enhancements for IAB

The IAB system architecture may also supports the following physical layer features: mechanisms for discovery of IAB-nodes and management of backhaul links in both SA and NSA deployments, taking into account the half-duplex constraint at an IAB-node and multi-hop topologies, including: solutions reusing the same set of SSBs used for access UEs and solutions which use of SSBs which are orthogonal (TDM and/or FDM) with SSBs used for access UEs, CSI-RS-based IAB-node discovery in synchronized deployments, backhaul link RSRP/RSRQ RRM measurements which are SSB-based and CSI-RS based; and enhancements to support configuration of backhaul RACH resources with different occasions, longer RACH periodicities, and additional preamble formats allowing for longer RTT, compared to access RACH resources without impacting Rel-15 UEs; enhancements to Beam Failure Recovery and Radio Link Failure procedures, including solutions to avoid RLF at a child IAB-node due to parent backhaul link failure; mechanisms for supporting both in-band and out-of-band relaying by multiplexing access and backhaul links in time (TDM), frequency (FDM), or space (SDM) under a per-link half-duplex constraint at the IAB-node and across multiple backhaul hops, including: semi-static configuration for IAB-node DU resources, dynamic indication to an IAB-node of the availability of soft resources for an IAB-node DU, and power control/coordination for FDM/SDM of access and backhaul links; OTA timing alignment across multiple backhaul hops, including: mechanisms for DL timing alignment across IAB-nodes, alignment of an IAB-node's UL transmission timing and DL transmission timing, and alignment of an IAB-node's UL reception timing and DL reception timing; inter-IAB-node cross-link interference (CLI) measurements and measurement coordination/configuration; and support of up to 1024QAM for backhaul links.

IAB-node RACH: IAB supports the ability of network flexibility to configure backhaul RACH resources with different occasions, longer RACH periodicities, and additional preamble formats allowing for longer RTT, compared to access RACH resources without impacting Rel-15 UEs. Based on Rel-15 PRACH configurations, the network is allowed to configure offset(s) for PRACH occasions for the MT of IAB-node(s), in order to TDM backhaul RACH resources across adjacent hops.

Backhaul link management: An IAB-node supports mechanisms for detecting/recovering from backhaul link failure based on Rel-15 mechanisms. Enhancements to Beam Failure Recovery and Radio Link Failure procedures may also include enhancements to support interaction between Beam Failure Recovery success indication and RLF; and enhancements to existing beam management procedures for faster beam switching/coordination/recovery to avoid backhaul link outages should be considered for IAB-nodes. Additional backhaul link condition notification mechanisms (e.g., if the parent IAB-node's backhaul link fails) from the parent IAB-node DU to the child IAB-node, as well as corresponding IAB-node behaviors, may be included.

FIG. 4 illustrates an example architecture of a system 400 of a network, in accordance with various embodiments. The following description is provided for an example system 400 that operates in conjunction with the LTE system standards and 5G or NR system standards as provided by 3GPP technical specifications. However, the example embodiments are not limited in this regard and the described embodiments may apply to other networks that benefit from the principles described herein, such as future 3GPP systems (e.g., Sixth Generation (6G)) systems, IEEE 802.16 protocols (e.g., WMAN, WiMAX, etc.), or the like.

As shown by FIG. 4, the system 400 includes UE 401 a and UE 401 b (collectively referred to as “UEs 401” or “UE 401”). In this example, UEs 401 are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks), but may also comprise any mobile or non-mobile computing device, such as consumer electronics devices, cellular phones, smartphones, feature phones, tablet computers, wearable computer devices, personal digital assistants (PDAs), pagers, wireless handsets, desktop computers, laptop computers, in-vehicle infotainment (IVI), in-car entertainment (ICE) devices, an Instrument Cluster (IC), head-up display (HUD) devices, onboard diagnostic (OBD) devices, dashtop mobile equipment (DME), mobile data terminals (MDTs), Electronic Engine Management System (EEMS), electronic/engine control units (ECUs), electronic/engine control modules (ECMs), embedded systems, microcontrollers, control modules, engine management systems (EMS), networked or “smart” appliances, MTC devices, M2M, IoT devices, and/or the like.

In some embodiments, any of the UEs 401 may be IoT UEs, which may comprise a network access layer designed for low-power IoT applications utilizing short-lived UE connections. An IoT UE can utilize technologies such as M2M or MTC for exchanging data with an MTC server or device via a PLMN, ProSe or D2D communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network describes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The IoT UEs may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate the connections of the IoT network.

The UEs 401 may be configured to connect, for example, communicatively couple, with a RAN 410. In embodiments, the RAN 410 may be an NG RAN or a 5G RAN, an E-UTRAN, or a legacy RAN, such as a UTRAN or GERAN. As used herein, the term “NG RAN” or the like may refer to a RAN 410 that operates in an NR or 5G system 400, and the term “E-UTRAN” or the like may refer to a RAN 410 that operates in an LTE or 4G system 400. The UEs 401 utilize connections (or channels) 403 and 404, respectively, each of which comprises a physical communications interface or layer (discussed in further detail below).

In this example, the connections 403 and 404 are illustrated as an air interface to enable communicative coupling, and can be consistent with cellular communications protocols, such as a GSM protocol, a CDMA network protocol, a PTT protocol, a POC protocol, a UMTS protocol, a 3GPP LTE protocol, a 5G protocol, a NR protocol, and/or any of the other communications protocols discussed herein. In embodiments, the UEs 401 may directly exchange communication data via a ProSe interface 405. The ProSe interface 405 may alternatively be referred to as a SL interface 405 and may comprise one or more logical channels, including but not limited to a PSCCH, a PSSCH, a PSDCH, and a PSBCH.

The UE 401 b is shown to be configured to access an AP 406 (also referred to as “WLAN node 406,” “WLAN 406,” “WLAN Termination 406,” “WT 406” or the like) via connection 407. The connection 407 can comprise a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein the AP 406 would comprise a wireless fidelity (Wi-Fi®) router. In this example, the AP 406 is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below). In various embodiments, the UE 401 b, RAN 410, and AP 406 may be configured to utilize LWA operation and/or LWIP operation. The LWA operation may involve the UE 401 b in RRC_CONNECTED being configured by a RAN node 411 a-b to utilize radio resources of LTE and WLAN. LWIP operation may involve the UE 401 b using WLAN radio resources (e.g., connection 407) via IPsec protocol tunneling to authenticate and encrypt packets (e.g., IP packets) sent over the connection 407. IPsec tunneling may include encapsulating the entirety of original IP packets and adding a new packet header, thereby protecting the original header of the IP packets.

The RAN 410 can include one or more AN nodes or RAN nodes 411 a and 411 b (collectively referred to as “RAN nodes 411” or “RAN node 411”) that enable the connections 403 and 404. As used herein, the terms “access node,” “access point,” or the like may describe equipment that provides the radio baseband functions for data and/or voice connectivity between a network and one or more users. These access nodes can be referred to as BS, gNBs, RAN nodes, eNBs, NodeBs, RSUs, TRxPs or TRPs, and so forth, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). As used herein, the term “NG RAN node” or the like may refer to a RAN node 411 that operates in an NR or 5G system 400 (for example, a gNB), and the term “E-UTRAN node” or the like may refer to a RAN node 411 that operates in an LTE or 4G system 400 (e.g., an eNB). According to various embodiments, the RAN nodes 411 may be implemented as one or more of a dedicated physical device such as a macrocell base station, and/or a low power (LP) base station for providing femtocells, picocells or other like cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells.

In some embodiments, all or parts of the RAN nodes 411 may be implemented as one or more software entities running on server computers as part of a virtual network, which may be referred to as a CRAN and/or a virtual baseband unit pool (vBBUP). In these embodiments, the CRAN or vBBUP may implement a RAN function split, such as a PDCP split wherein RRC and PDCP layers are operated by the CRAN/vBBUP and other L2 protocol entities are operated by individual RAN nodes 411; a MAC/PHY split wherein RRC, PDCP, RLC, and MAC layers are operated by the CRAN/vBBUP and the PHY layer is operated by individual RAN nodes 411; or a “lower PHY” split wherein RRC, PDCP, RLC, MAC layers and upper portions of the PHY layer are operated by the CRAN/vBBUP and lower portions of the PHY layer are operated by individual RAN nodes 411. This virtualized framework allows the freed-up processor cores of the RAN nodes 411 to perform other virtualized applications. In some implementations, an individual RAN node 411 may represent individual gNB-DUs that are connected to a gNB-CU via individual F1 interfaces (not shown by FIG. 4). In these implementations, the gNB-DUs may include one or more remote radio heads or RFEMs (see, e.g., FIG. 7), and the gNB-CU may be operated by a server that is located in the RAN 410 (not shown) or by a server pool in a similar manner as the CRAN/vBBUP. Additionally or alternatively, one or more of the RAN nodes 411 may be next generation eNBs (ng-eNBs), which are RAN nodes that provide E-UTRA user plane and control plane protocol terminations toward the UEs 401, and are connected to a 5GC (e.g., CN 620 of FIG. 6) via an NG interface (discussed infra).

In V2X scenarios one or more of the RAN nodes 411 may be or act as RSUs. The term “Road Side Unit” or “RSU” may refer to any transportation infrastructure entity used for V2X communications. An RSU may be implemented in or by a suitable RAN node or a stationary (or relatively stationary) UE, where an RSU implemented in or by a UE may be referred to as a “UE-type RSU,” an RSU implemented in or by an eNB may be referred to as an “eNB-type RSU,” an RSU implemented in or by a gNB may be referred to as a “gNB-type RSU,” and the like. In one example, an RSU is a computing device coupled with radio frequency circuitry located on a roadside that provides connectivity support to passing vehicle UEs 401 (vUEs 401). The RSU may also include internal data storage circuitry to store intersection map geometry, traffic statistics, media, as well as applications/software to sense and control ongoing vehicular and pedestrian traffic. The RSU may operate on the 5.9 GHz Direct Short Range Communications (DSRC) band to provide very low latency communications required for high speed events, such as crash avoidance, traffic warnings, and the like. Additionally or alternatively, the RSU may operate on the cellular V2X band to provide the aforementioned low latency communications, as well as other cellular communications services. Additionally or alternatively, the RSU may operate as a Wi-Fi hotspot (2.4 GHz band) and/or provide connectivity to one or more cellular networks to provide uplink and downlink communications. The computing device(s) and some or all of the radiofrequency circuitry of the RSU may be packaged in a weatherproof enclosure suitable for outdoor installation, and may include a network interface controller to provide a wired connection (e.g., Ethernet) to a traffic signal controller and/or a backhaul network.

Any of the RAN nodes 411 can terminate the air interface protocol and can be the first point of contact for the UEs 401. In some embodiments, any of the RAN nodes 411 can fulfill various logical functions for the RAN 410 including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

In embodiments, the UEs 401 can be configured to communicate using OFDM communication signals with each other or with any of the RAN nodes 411 over a multicarrier communication channel in accordance with various communication techniques, such as, but not limited to, an OFDMA communication technique (e.g., for downlink communications) or a SC-FDMA communication technique (e.g., for uplink and ProSe or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers.

In some embodiments, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes 411 to the UEs 401, while uplink transmissions can utilize similar techniques. The grid can be a time-frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane representation is a common practice for OFDM systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time-frequency unit in a resource grid is denoted as a resource element. Each resource grid comprises a number of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a collection of resource elements; in the frequency domain, this may represent the smallest quantity of resources that currently can be allocated. There are several different physical downlink channels that are conveyed using such resource blocks.

According to various embodiments, the UEs 401 and the RAN nodes 411 communicate data (for example, transmit and receive) data over a licensed medium (also referred to as the “licensed spectrum” and/or the “licensed band”) and an unlicensed shared medium (also referred to as the “unlicensed spectrum” and/or the “unlicensed band”). The licensed spectrum may include channels that operate in the frequency range of approximately 400 MHz to approximately 3.8 GHz, whereas the unlicensed spectrum may include the 5 GHz band.

To operate in the unlicensed spectrum, the UEs 401 and the RAN nodes 411 may operate using LAA, eLAA, and/or feLAA mechanisms. In these implementations, the UEs 401 and the RAN nodes 411 may perform one or more known medium-sensing operations and/or carrier-sensing operations in order to determine whether one or more channels in the unlicensed spectrum is unavailable or otherwise occupied prior to transmitting in the unlicensed spectrum. The medium/carrier sensing operations may be performed according to a listen-before-talk (LBT) protocol.

LBT is a mechanism whereby equipment (for example, UEs 401 RAN nodes 411, etc.) senses a medium (for example, a channel or carrier frequency) and transmits when the medium is sensed to be idle (or when a specific channel in the medium is sensed to be unoccupied). The medium sensing operation may include CCA, which utilizes at least ED to determine the presence or absence of other signals on a channel in order to determine if a channel is occupied or clear. This LBT mechanism allows cellular/LAA networks to coexist with incumbent systems in the unlicensed spectrum and with other LAA networks. ED may include sensing RF energy across an intended transmission band for a period of time and comparing the sensed RF energy to a predefined or configured threshold.

Typically, the incumbent systems in the 5 GHz band are WLANs based on IEEE 802.11 technologies. WLAN employs a contention-based channel access mechanism, called CSMA/CA. Here, when a WLAN node (e.g., a mobile station (MS) such as UE 401, AP 406, or the like) intends to transmit, the WLAN node may first perform CCA before transmission. Additionally, a backoff mechanism is used to avoid collisions in situations where more than one WLAN node senses the channel as idle and transmits at the same time. The backoff mechanism may be a counter that is drawn randomly within the CWS, which is increased exponentially upon the occurrence of collision and reset to a minimum value when the transmission succeeds. The LBT mechanism designed for LAA is somewhat similar to the CSMA/CA of WLAN. In some implementations, the LBT procedure for DL or UL transmission bursts including PDSCH or PUSCH transmissions, respectively, may have an LAA contention window that is variable in length between X and Y ECCA slots, where X and Y are minimum and maximum values for the CWSs for LAA. In one example, the minimum CWS for an LAA transmission may be 9 microseconds; however, the size of the CWS and a MCOT (for example, a transmission burst) may be based on governmental regulatory requirements.

The LAA mechanisms are built upon CA technologies of LTE-Advanced systems. In CA, each aggregated carrier is referred to as a CC. A CC may have a bandwidth of 1.4, 3, 5, 10, 15 or 20 MHz and a maximum of five CCs can be aggregated, and therefore, a maximum aggregated bandwidth is 100 MHz. In FDD systems, the number of aggregated carriers can be different for DL and UL, where the number of UL CCs is equal to or lower than the number of DL component carriers. In some cases, individual CCs can have a different bandwidth than other CCs. In TDD systems, the number of CCs as well as the bandwidths of each CC is usually the same for DL and UL.

CA also comprises individual serving cells to provide individual CCs. The coverage of the serving cells may differ, for example, because CCs on different frequency bands will experience different pathloss. A primary service cell or PCell may provide a PCC for both UL and DL, and may handle RRC and NAS related activities. The other serving cells are referred to as SCells, and each SCell may provide an individual SCC for both UL and DL. The SCCs may be added and removed as required, while changing the PCC may require the UE 401 to undergo a handover. In LAA, eLAA, and feLAA, some or all of the SCells may operate in the unlicensed spectrum (referred to as “LAA SCells”), and the LAA SCells are assisted by a PCell operating in the licensed spectrum. When a UE is configured with more than one LAA SCell, the UE may receive UL grants on the configured LAA SCells indicating different PUSCH starting positions within a same subframe.

The PDSCH carries user data and higher-layer signaling to the UEs 401. The PDCCH carries information about the transport format and resource allocations related to the PDSCH channel, among other things. It may also inform the UEs 401 about the transport format, resource allocation, and HARQ information related to the uplink shared channel. Typically, downlink scheduling (assigning control and shared channel resource blocks to the UE 401 b within a cell) may be performed at any of the RAN nodes 411 based on channel quality information fed back from any of the UEs 401. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of the UEs 401.

The PDCCH uses CCEs to convey the control information. Before being mapped to resource elements, the PDCCH complex-valued symbols may first be organized into quadruplets, which may then be permuted using a sub-block interleaver for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements known as REGs. Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of the DCI and the channel condition. There can be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=1, 2, 4, or 8).

Some embodiments may use concepts for resource allocation for control channel information that are an extension of the above-described concepts. For example, some embodiments may utilize an EPDCCH that uses PDSCH resources for control information transmission. The EPDCCH may be transmitted using one or more ECCEs. Similar to above, each ECCE may correspond to nine sets of four physical resource elements known as an EREGs. An ECCE may have other numbers of EREGs in some situations.

The RAN nodes 411 may be configured to communicate with one another via interface 412. In embodiments where the system 400 is an LTE system (e.g., when CN 420 is an EPC 520 as in FIG. 5), the interface 412 may be an X2 interface 412. The X2 interface may be defined between two or more RAN nodes 411 (e.g., two or more eNBs and the like) that connect to EPC 420, and/or between two eNBs connecting to EPC 420. In some implementations, the X2 interface may include an X2 user plane interface (X2-U) and an X2 control plane interface (X2-C). The X2-U may provide flow control mechanisms for user data packets transferred over the X2 interface, and may be used to communicate information about the delivery of user data between eNBs. For example, the X2-U may provide specific sequence number information for user data transferred from a MeNB to an SeNB; information about successful in sequence delivery of PDCP PDUs to a UE 401 from an SeNB for user data; information of PDCP PDUs that were not delivered to a UE 401; information about a current minimum desired buffer size at the SeNB for transmitting to the UE user data; and the like. The X2-C may provide intra-LTE access mobility functionality, including context transfers from source to target eNBs, user plane transport control, etc.; load management functionality; as well as inter-cell interference coordination functionality.

In embodiments where the system 400 is a 5G or NR system (e.g., when CN 420 is an 5GC 620 as in FIG. 6), the interface 412 may be an Xn interface 412. The Xn interface is defined between two or more RAN nodes 411 (e.g., two or more gNBs and the like) that connect to 5GC 420, between a RAN node 411 (e.g., a gNB) connecting to 5GC 420 and an eNB, and/or between two eNBs connecting to 5GC 420. In some implementations, the Xn interface may include an Xn user plane (Xn-U) interface and an Xn control plane (Xn-C) interface. The Xn-U may provide non-guaranteed delivery of user plane PDUs and support/provide data forwarding and flow control functionality. The Xn-C may provide management and error handling functionality, functionality to manage the Xn-C interface; mobility support for UE 401 in a connected mode (e.g., CM-CONNECTED) including functionality to manage the UE mobility for connected mode between one or more RAN nodes 411. The mobility support may include context transfer from an old (source) serving RAN node 411 to new (target) serving RAN node 411; and control of user plane tunnels between old (source) serving RAN node 411 to new (target) serving RAN node 411. A protocol stack of the Xn-U may include a transport network layer built on Internet Protocol (IP) transport layer, and a GTP-U layer on top of a UDP and/or IP layer(s) to carry user plane PDUs. The Xn-C protocol stack may include an application layer signaling protocol (referred to as Xn Application Protocol (Xn-AP)) and a transport network layer that is built on SCTP. The SCTP may be on top of an IP layer, and may provide the guaranteed delivery of application layer messages. In the transport IP layer, point-to-point transmission is used to deliver the signaling PDUs. In other implementations, the Xn-U protocol stack and/or the Xn-C protocol stack may be same or similar to the user plane and/or control plane protocol stack(s) shown and described herein.

The RAN 410 is shown to be communicatively coupled to a core network-in this embodiment, core network (CN) 420. The CN 420 may comprise a plurality of network elements 422, which are configured to offer various data and telecommunications services to customers/subscribers (e.g., users of UEs 401) who are connected to the CN 420 via the RAN 410. The components of the CN 420 may be implemented in one physical node or separate physical nodes including components to read and execute instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium). In some embodiments, NFV may be utilized to virtualize any or all of the above-described network node functions via executable instructions stored in one or more computer-readable storage mediums (described in further detail below). A logical instantiation of the CN 420 may be referred to as a network slice, and a logical instantiation of a portion of the CN 420 may be referred to as a network sub-slice. NFV architectures and infrastructures may be used to virtualize one or more network functions, alternatively performed by proprietary hardware, onto physical resources comprising a combination of industry-standard server hardware, storage hardware, or switches. In other words, NFV systems can be used to execute virtual or reconfigurable implementations of one or more EPC components/functions.

Generally, the application server 430 may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS PS domain, LTE PS data services, etc.). The application server 430 can also be configured to support one or more communication services (e.g., VoIP sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs 401 via the EPC 420.

In embodiments, the CN 420 may be a 5GC (referred to as “5GC 420” or the like), and the RAN 410 may be connected with the CN 420 via an NG interface 413. In embodiments, the NG interface 413 may be split into two parts, an NG user plane (NG-U) interface 414, which carries traffic data between the RAN nodes 411 and a UPF, and the S1 control plane (NG-C) interface 415, which is a signaling interface between the RAN nodes 411 and AMFs. Embodiments where the CN 420 is a 5GC 420 are discussed in more detail with regard to FIG. 6.

In embodiments, the CN 420 may be a 5G CN (referred to as “5GC 420” or the like), while in other embodiments, the CN 420 may be an EPC). Where CN 420 is an EPC (referred to as “EPC 420” or the like), the RAN 410 may be connected with the CN 420 via an S1 interface 413. In embodiments, the S1 interface 413 may be split into two parts, an S1 user plane (S1-U) interface 414, which carries traffic data between the RAN nodes 411 and the S-GW, and the S1-MME interface 415, which is a signaling interface between the RAN nodes 411 and MMEs.

FIG. 5 illustrates an example architecture of a system 500 including a first CN 520, in accordance with various embodiments. In this example, system 500 may implement the LTE standard wherein the CN 520 is an EPC 520 that corresponds with CN 420 of FIG. 4. Additionally, the UE 501 may be the same or similar as the UEs 401 of FIG. 4, and the E-UTRAN 510 may be a RAN that is the same or similar to the RAN 410 of FIG. 4, and which may include RAN nodes 411 discussed previously. The CN 520 may comprise MMEs 521, an S-GW 522, a P-GW 523, a HSS 524, and a SGSN 525.

The MMEs 521 may be similar in function to the control plane of legacy SGSN, and may implement MM functions to keep track of the current location of a UE 501. The MMEs 521 may perform various MM procedures to manage mobility aspects in access such as gateway selection and tracking area list management. MM (also referred to as “EPS MM” or “EMM” in E-UTRAN systems) may refer to all applicable procedures, methods, data storage, etc. that are used to maintain knowledge about a present location of the UE 501, provide user identity confidentiality, and/or perform other like services to users/subscribers. Each UE 501 and the MME 521 may include an MM or EMM sublayer, and an MM context may be established in the UE 501 and the MME 521 when an attach procedure is successfully completed. The MM context may be a data structure or database object that stores MM-related information of the UE 501. The MMEs 521 may be coupled with the HSS 524 via an S6a reference point, coupled with the SGSN 525 via an S3 reference point, and coupled with the S-GW 522 via an S11 reference point.

The SGSN 525 may be a node that serves the UE 501 by tracking the location of an individual UE 501 and performing security functions. In addition, the SGSN 525 may perform Inter-EPC node signaling for mobility between 2G/3G and E-UTRAN 3GPP access networks; PDN and S-GW selection as specified by the MMEs 521; handling of UE 501 time zone functions as specified by the MMEs 521; and MME selection for handovers to E-UTRAN 3GPP access network. The S3 reference point between the MMEs 521 and the SGSN 525 may enable user and bearer information exchange for inter-3GPP access network mobility in idle and/or active states.

The HSS 524 may comprise a database for network users, including subscription-related information to support the network entities' handling of communication sessions. The EPC 520 may comprise one or several HSSs 524, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS 524 can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc. An S6a reference point between the HSS 524 and the MMEs 521 may enable transfer of subscription and authentication data for authenticating/authorizing user access to the EPC 520 between HSS 524 and the MMEs 521.

The S-GW 522 may terminate the S1 interface 413 (“S1-U” in FIG. 5) toward the RAN 510, and routes data packets between the RAN 510 and the EPC 520. In addition, the S-GW 522 may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities may include lawful intercept, charging, and some policy enforcement. The S11 reference point between the S-GW 522 and the MMEs 521 may provide a control plane between the MMEs 521 and the S-GW 522. The S-GW 522 may be coupled with the P-GW 523 via an S5 reference point.

The P-GW 523 may terminate an SGi interface toward a PDN 530. The P-GW 523 may route data packets between the EPC 520 and external networks such as a network including the application server 430 (alternatively referred to as an “AF”) via an IP interface 425 (see e.g., FIG. 4). In embodiments, the P-GW 523 may be communicatively coupled to an application server (application server 430 of FIG. 4 or PDN 530 in FIG. 5) via an IP communications interface 425 (see, e.g., FIG. 4). The S5 reference point between the P-GW 523 and the S-GW 522 may provide user plane tunneling and tunnel management between the P-GW 523 and the S-GW 522. The S5 reference point may also be used for S-GW 522 relocation due to UE 501 mobility and if the S-GW 522 needs to connect to a non-collocated P-GW 523 for the required PDN connectivity. The P-GW 523 may further include a node for policy enforcement and charging data collection (e.g., PCEF (not shown)). Additionally, the SGi reference point between the P-GW 523 and the packet data network (PDN) 530 may be an operator external public, a private PDN, or an intra operator packet data network, for example, for provision of IMS services. The P-GW 523 may be coupled with a PCRF 526 via a Gx reference point.

PCRF 526 is the policy and charging control element of the EPC 520. In a non-roaming scenario, there may be a single PCRF 526 in the Home Public Land Mobile Network (HPLMN) associated with a UE 501's Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with a UE 501's IP-CAN session, a Home PCRF (H-PCRF) within an HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF 526 may be communicatively coupled to the application server 530 via the P-GW 523. The application server 530 may signal the PCRF 526 to indicate a new service flow and select the appropriate QoS and charging parameters. The PCRF 526 may provision this rule into a PCEF (not shown) with the appropriate TFT and QCI, which commences the QoS and charging as specified by the application server 530. The Gx reference point between the PCRF 526 and the P-GW 523 may allow for the transfer of QoS policy and charging rules from the PCRF 526 to PCEF in the P-GW 523. An Rx reference point may reside between the PDN 530 (or “AF 530”) and the PCRF 526.

FIG. 6 illustrates an architecture of a system 600 including a second CN 620 in accordance with various embodiments. The system 600 is shown to include a UE 601, which may be the same or similar to the UEs 401 and UE 501 discussed previously; a (R)AN 610, which may be the same or similar to the RAN 410 and RAN 510 discussed previously, and which may include RAN nodes 411 discussed previously; and a DN 603, which may be, for example, operator services, Internet access or 3rd party services; and a 5GC 620. The 5GC 620 may include an AUSF 622; an AMF 621; a SMF 624; a NEF 623; a PCF 626; a NRF 625; a UDM 627; an AF 628; a UPF 602; and a NSSF 629.

The UPF 602 may act as an anchor point for intra-RAT and inter-RAT mobility, an external PDU session point of interconnect to DN 603, and a branching point to support multi-homed PDU session. The UPF 602 may also perform packet routing and forwarding, perform packet inspection, enforce the user plane part of policy rules, lawfully intercept packets (UP collection), perform traffic usage reporting, perform QoS handling for a user plane (e.g., packet filtering, gating, UL/DL rate enforcement), perform Uplink Traffic verification (e.g., SDF to QoS flow mapping), transport level packet marking in the uplink and downlink, and perform downlink packet buffering and downlink data notification triggering. UPF 602 may include an uplink classifier to support routing traffic flows to a data network. The DN 603 may represent various network operator services, Internet access, or third party services. DN 603 may include, or be similar to, application server 430 discussed previously. The UPF 602 may interact with the SMF 624 via an N4 reference point between the SMF 624 and the UPF 602.

The AUSF 622 may store data for authentication of UE 601 and handle authentication-related functionality. The AUSF 622 may facilitate a common authentication framework for various access types. The AUSF 622 may communicate with the AMF 621 via an N12 reference point between the AMF 621 and the AUSF 622; and may communicate with the UDM 627 via an N13 reference point between the UDM 627 and the AUSF 622. Additionally, the AUSF 622 may exhibit an Nausf service-based interface.

The AMF 621 may be responsible for registration management (e.g., for registering UE 601, etc.), connection management, reachability management, mobility management, and lawful interception of AMF-related events, and access authentication and authorization. The AMF 621 may be a termination point for the N11 reference point between the AMF 621 and the SMF 624. The AMF 621 may provide transport for SM messages between the UE 601 and the SMF 624, and act as a transparent proxy for routing SM messages. AMF 621 may also provide transport for SMS messages between UE 601 and an SMSF (not shown by FIG. 6). AMF 621 may act as SEAF, which may include interaction with the AUSF 622 and the UE 601, receipt of an intermediate key that was established as a result of the UE 601 authentication process. Where USIM based authentication is used, the AMF 621 may retrieve the security material from the AUSF 622. AMF 621 may also include a SCM function, which receives a key from the SEA that it uses to derive access-network specific keys. Furthermore, AMF 621 may be a termination point of a RAN CP interface, which may include or be an N2 reference point between the (R)AN 610 and the AMF 621; and the AMF 621 may be a termination point of NAS (N1) signaling, and perform NAS ciphering and integrity protection.

AMF 621 may also support NAS signaling with a UE 601 over an N3 IWF interface. The N3IWF may be used to provide access to untrusted entities. N3IWF may be a termination point for the N2 interface between the (R)AN 610 and the AMF 621 for the control plane, and may be a termination point for the N3 reference point between the (R)AN 610 and the UPF 602 for the user plane. As such, the AMF 621 may handle N2 signaling from the SMF 624 and the AMF 621 for PDU sessions and QoS, encapsulate/de-encapsulate packets for IPSec and N3 tunneling, mark N3 user-plane packets in the uplink, and enforce QoS corresponding to N3 packet marking taking into account QoS requirements associated with such marking received over N2. N3IWF may also relay uplink and downlink control-plane NAS signaling between the UE 601 and AMF 621 via an N1 reference point between the UE 601 and the AMF 621, and relay uplink and downlink user-plane packets between the UE 601 and UPF 602. The N3IWF also provides mechanisms for IPsec tunnel establishment with the UE 601. The AMF 621 may exhibit an Namf service-based interface, and may be a termination point for an N14 reference point between two AMFs 621 and an N17 reference point between the AMF 621 and a 5G-EIR (not shown by FIG. 6).

The UE 601 may need to register with the AMF 621 in order to receive network services. RM is used to register or deregister the UE 601 with the network (e.g., AMF 621), and establish a UE context in the network (e.g., AMF 621). The UE 601 may operate in an RM-REGISTERED state or an RM-DEREGISTERED state. In the RM DEREGISTERED state, the UE 601 is not registered with the network, and the UE context in AMF 621 holds no valid location or routing information for the UE 601 so the UE 601 is not reachable by the AMF 621. In the RM REGISTERED state, the UE 601 is registered with the network, and the UE context in AMF 621 may hold a valid location or routing information for the UE 601 so the UE 601 is reachable by the AMF 621. In the RM-REGISTERED state, the UE 601 may perform mobility Registration Update procedures, perform periodic Registration Update procedures triggered by expiration of the periodic update timer (e.g., to notify the network that the UE 601 is still active), and perform a Registration Update procedure to update UE capability information or to re-negotiate protocol parameters with the network, among others.

The AMF 621 may store one or more RM contexts for the UE 601, where each RM context is associated with a specific access to the network. The RM context may be a data structure, database object, etc. that indicates or stores, inter alia, a registration state per access type and the periodic update timer. The AMF 621 may also store a 5GC MM context that may be the same or similar to the (E)MM context discussed previously. In various embodiments, the AMF 621 may store a CE mode B Restriction parameter of the UE 601 in an associated MM context or RM context. The AMF 621 may also derive the value, when needed, from the UE's usage setting parameter already stored in the UE context (and/or MM/RM context).

CM may be used to establish and release a signaling connection between the UE 601 and the AMF 621 over the N1 interface. The signaling connection is used to enable NAS signaling exchange between the UE 601 and the CN 620, and comprises both the signaling connection between the UE and the AN (e.g., RRC connection or UE-N3IWF connection for non-3GPP access) and the N2 connection for the UE 601 between the AN (e.g., RAN 610) and the AMF 621. The UE 601 may operate in one of two CM states, CM-IDLE mode or CM-CONNECTED mode. When the UE 601 is operating in the CM-IDLE state/mode, the UE 601 may have no NAS signaling connection established with the AMF 621 over the N1 interface, and there may be (R)AN 610 signaling connection (e.g., N2 and/or N3 connections) for the UE 601. When the UE 601 is operating in the CM-CONNECTED state/mode, the UE 601 may have an established NAS signaling connection with the AMF 621 over the N1 interface, and there may be a (R)AN 610 signaling connection (e.g., N2 and/or N3 connections) for the UE 601. Establishment of an N2 connection between the (R)AN 610 and the AMF 621 may cause the UE 601 to transition from CM-IDLE mode to CM-CONNECTED mode, and the UE 601 may transition from the CM-CONNECTED mode to the CM-IDLE mode when N2 signaling between the (R)AN 610 and the AMF 621 is released.

The SMF 624 may be responsible for SM (e.g., session establishment, modify and release, including tunnel maintain between UPF and AN node); UE IP address allocation and management (including optional authorization); selection and control of UP function; configuring traffic steering at UPF to route traffic to proper destination; termination of interfaces toward policy control functions; controlling part of policy enforcement and QoS; lawful intercept (for SM events and interface to LI system); termination of SM parts of NAS messages; downlink data notification; initiating AN specific SM information, sent via AMF over N2 to AN; and determining SSC mode of a session. SM may refer to management of a PDU session, and a PDU session or “session” may refer to a PDU connectivity service that provides or enables the exchange of PDUs between a UE 601 and a data network (DN) 603 identified by a Data Network Name (DNN). PDU sessions may be established upon UE 601 request, modified upon UE 601 and 5GC 620 request, and released upon UE 601 and 5GC 620 request using NAS SM signaling exchanged over the N1 reference point between the UE 601 and the SMF 624. Upon request from an application server, the 5GC 620 may trigger a specific application in the UE 601. In response to receipt of the trigger message, the UE 601 may pass the trigger message (or relevant parts/information of the trigger message) to one or more identified applications in the UE 601. The identified application(s) in the UE 601 may establish a PDU session to a specific DNN. The SMF 624 may check whether the UE 601 requests are compliant with user subscription information associated with the UE 601. In this regard, the SMF 624 may retrieve and/or request to receive update notifications on SMF 624 level subscription data from the UDM 627.

The SMF 624 may include the following roaming functionality: handling local enforcement to apply QoS SLAs (VPLMN); charging data collection and charging interface (VPLMN); lawful intercept (in VPLMN for SM events and interface to LI system); and support for interaction with external DN for transport of signaling for PDU session authorization/authentication by external DN. An N16 reference point between two SMFs 624 may be included in the system 600, which may be between another SMF 624 in a visited network and the SMF 624 in the home network in roaming scenarios. Additionally, the SMF 624 may exhibit the Nsmf service-based interface.

The NEF 623 may provide means for securely exposing the services and capabilities provided by 3GPP network functions for third party, internal exposure/re-exposure, Application Functions (e.g., AF 628), edge computing or fog computing systems, etc. In such embodiments, the NEF 623 may authenticate, authorize, and/or throttle the AFs. NEF 623 may also translate information exchanged with the AF 628 and information exchanged with internal network functions. For example, the NEF 623 may translate between an AF-Service-Identifier and an internal 5GC information. NEF 623 may also receive information from other network functions (NFs) based on exposed capabilities of other network functions. This information may be stored at the NEF 623 as structured data, or at a data storage NF using standardized interfaces. The stored information can then be re-exposed by the NEF 623 to other NFs and AFs, and/or used for other purposes such as analytics. Additionally, the NEF 623 may exhibit an Nnef service-based interface.

The NRF 625 may support service discovery functions, receive NF discovery requests from NF instances, and provide the information of the discovered NF instances to the NF instances. NRF 625 also maintains information of available NF instances and their supported services. As used herein, the terms “instantiate,” “instantiation,” and the like may refer to the creation of an instance, and an “instance” may refer to a concrete occurrence of an object, which may occur, for example, during execution of program code. Additionally, the NRF 625 may exhibit the Nnrf service-based interface.

The PCF 626 may provide policy rules to control plane function(s) to enforce them, and may also support unified policy framework to govern network behavior. The PCF 626 may also implement an FE to access subscription information relevant for policy decisions in a UDR of the UDM 627. The PCF 626 may communicate with the AMF 621 via an N15 reference point between the PCF 626 and the AMF 621, which may include a PCF 626 in a visited network and the AMF 621 in case of roaming scenarios. The PCF 626 may communicate with the AF 628 via an N5 reference point between the PCF 626 and the AF 628; and with the SMF 624 via an N7 reference point between the PCF 626 and the SMF 624. The system 600 and/or CN 620 may also include an N24 reference point between the PCF 626 (in the home network) and a PCF 626 in a visited network. Additionally, the PCF 626 may exhibit an Npcf service-based interface.

The UDM 627 may handle subscription-related information to support the network entities' handling of communication sessions, and may store subscription data of UE 601. For example, subscription data may be communicated between the UDM 627 and the AMF 621 via an N8 reference point between the UDM 627 and the AMF. The UDM 627 may include two parts, an application FE and a UDR (the FE and UDR are not shown by FIG. 6). The UDR may store subscription data and policy data for the UDM 627 and the PCF 626, and/or structured data for exposure and application data (including PFDs for application detection, application request information for multiple UEs 601) for the NEF 623. The Nudr service-based interface may be exhibited by the UDR 221 to allow the UDM 627, PCF 626, and NEF 623 to access a particular set of the stored data, as well as to read, update (e.g., add, modify), delete, and subscribe to notification of relevant data changes in the UDR. The UDM may include a UDM-FE, which is in charge of processing credentials, location management, subscription management and so on. Several different front ends may serve the same user in different transactions. The UDM-FE accesses subscription information stored in the UDR and performs authentication credential processing, user identification handling, access authorization, registration/mobility management, and subscription management. The UDR may interact with the SMF 624 via an N10 reference point between the UDM 627 and the SMF 624. UDM 627 may also support SMS management, wherein an SMS-FE implements the similar application logic as discussed previously. Additionally, the UDM 627 may exhibit the Nudm service-based interface.

The AF 628 may provide application influence on traffic routing, provide access to the NCE, and interact with the policy framework for policy control. The NCE may be a mechanism that allows the 5GC 620 and AF 628 to provide information to each other via NEF 623, which may be used for edge computing implementations. In such implementations, the network operator and third party services may be hosted close to the UE 601 access point of attachment to achieve an efficient service delivery through the reduced end-to-end latency and load on the transport network. For edge computing implementations, the 5GC may select a UPF 602 close to the UE 601 and execute traffic steering from the UPF 602 to DN 603 via the N6 interface. This may be based on the UE subscription data, UE location, and information provided by the AF 628. In this way, the AF 628 may influence UPF (re)selection and traffic routing. Based on operator deployment, when AF 628 is considered to be a trusted entity, the network operator may permit AF 628 to interact directly with relevant NFs. Additionally, the AF 628 may exhibit an Naf service-based interface.

The NSSF 629 may select a set of network slice instances serving the UE 601. The NSSF 629 may also determine allowed NSSAI and the mapping to the subscribed S-NSSAIs, if needed. The NSSF 629 may also determine the AMF set to be used to serve the UE 601, or a list of candidate AMF(s) 621 based on a suitable configuration and possibly by querying the NRF 625. The selection of a set of network slice instances for the UE 601 may be triggered by the AMF 621 with which the UE 601 is registered by interacting with the NSSF 629, which may lead to a change of AMF 621. The NSSF 629 may interact with the AMF 621 via an N22 reference point between AMF 621 and NSSF 629; and may communicate with another NSSF 629 in a visited network via an N31 reference point (not shown by FIG. 6). Additionally, the NSSF 629 may exhibit an Nnssf service-based interface.

As discussed previously, the CN 620 may include an SMSF, which may be responsible for SMS subscription checking and verification, and relaying SM messages to/from the UE 601 to/from other entities, such as an SMS-GMSC/IWMSC/SMS-router. The SMS may also interact with AMF 621 and UDM 627 for a notification procedure that the UE 601 is available for SMS transfer (e.g., set a UE not reachable flag, and notifying UDM 627 when UE 601 is available for SMS).

The CN 120 may also include other elements that are not shown by FIG. 6, such as a Data Storage system/architecture, a 5G-EIR, a SEPP, and the like. The Data Storage system may include a SDSF, an UDSF, and/or the like. Any NF may store and retrieve unstructured data into/from the UDSF (e.g., UE contexts), via N18 reference point between any NF and the UDSF (not shown by FIG. 6). Individual NFs may share a UDSF for storing their respective unstructured data or individual NFs may each have their own UDSF located at or near the individual NFs. Additionally, the UDSF may exhibit an Nudsf service-based interface (not shown by FIG. 6). The 5G-EIR may be an NF that checks the status of PEI for determining whether particular equipment/entities are blacklisted from the network; and the SEPP may be a non-transparent proxy that performs topology hiding, message filtering, and policing on inter-PLMN control plane interfaces.

Additionally, there may be many more reference points and/or service-based interfaces between the NF services in the NFs; however, these interfaces and reference points have been omitted from FIG. 6 for clarity. In one example, the CN 620 may include an Nx interface, which is an inter-CN interface between the MME (e.g., MME 521) and the AMF 621 in order to enable interworking between CN 620 and CN 520. Other example interfaces/reference points may include an N5g-EIR service-based interface exhibited by a 5G-EIR, an N27 reference point between the NRF in the visited network and the NRF in the home network; and an N31 reference point between the NSSF in the visited network and the NSSF in the home network.

FIG. 7 illustrates an example of infrastructure equipment 700 in accordance with various embodiments. The infrastructure equipment 700 (or “system 700”) may be implemented as a base station, radio head, RAN node such as the RAN nodes 411 and/or AP 406 shown and described previously, application server(s) 430, and/or any other element/device discussed herein. In other examples, the system 700 could be implemented in or by a UE.

The system 700 includes application circuitry 705, baseband circuitry 710, one or more radio front end modules (RFEMs) 715, memory circuitry 720, power management integrated circuitry (PMIC) 725, power tee circuitry 730, network controller circuitry 735, network interface connector 740, satellite positioning circuitry 745, and user interface 750. In some embodiments, the device 700 may include additional elements such as, for example, memory/storage, display, camera, sensor, or input/output (I/O) interface. In other embodiments, the components described below may be included in more than one device. For example, said circuitries may be separately included in more than one device for CRAN, vBBU, or other like implementations.

Application circuitry 705 includes circuitry such as, but not limited to one or more processors (or processor cores), cache memory, and one or more of low drop-out voltage regulators (LDOs), interrupt controllers, serial interfaces such as SPI, I2C or universal programmable serial interface module, real time clock (RTC), timer-counters including interval and watchdog timers, general purpose input/output (I/O or IO), memory card controllers such as Secure Digital (SD) MultiMediaCard (MMC) or similar, Universal Serial Bus (USB) interfaces, Mobile Industry Processor Interface (MIPI) interfaces and Joint Test Access Group (JTAG) test access ports. The processors (or cores) of the application circuitry 705 may be coupled with or may include memory/storage elements and may be configured to execute instructions stored in the memory/storage to enable various applications or operating systems to run on the system 700. In some implementations, the memory/storage elements may be on-chip memory circuitry, which may include any suitable volatile and/or non-volatile memory, such as DRAM, SRAM, EPROM, EEPROM, Flash memory, solid-state memory, and/or any other type of memory device technology, such as those discussed herein.

The processor(s) of application circuitry 705 may include, for example, one or more processor cores (CPUs), one or more application processors, one or more graphics processing units (GPUs), one or more reduced instruction set computing (RISC) processors, one or more Acorn RISC Machine (ARM) processors, one or more complex instruction set computing (CISC) processors, one or more digital signal processors (DSP), one or more FPGAs, one or more PLDs, one or more ASICs, one or more microprocessors or controllers, or any suitable combination thereof. In some embodiments, the application circuitry 705 may comprise, or may be, a special-purpose processor/controller to operate according to the various embodiments herein. As examples, the processor(s) of application circuitry 705 may include one or more may include one or more Apple A-series processors, Intel Pentium®, Core®, or Xeon® processor(s); Advanced Micro Devices (AMD) Ryzen® processor(s), Accelerated Processing Units (APUs), or Epyc® processors; ARM-based processor(s) licensed from ARM Holdings, Ltd. such as the ARM Cortex-A family of processors and the ThunderX2® provided by Cavium™, Inc.; a MIPS-based design from MIPS Technologies, Inc. such as MIPS Warrior P-class processors; and/or the like. In some embodiments, the system 700 may not utilize application circuitry 705, and instead may include a special-purpose processor/controller to process IP data received from an EPC or 5GC, for example.

In some implementations, the application circuitry 705 may include one or more hardware accelerators, which may be microprocessors, programmable processing devices, or the like. The one or more hardware accelerators may include, for example, computer vision (CV) and/or deep learning (DL) accelerators. As examples, the programmable processing devices may be one or more a field-programmable devices (FPDs) such as field-programmable gate arrays (FPGAs) and the like; programmable logic devices (PLDs) such as complex PLDs (CPLDs), high-capacity PLDs (HCPLDs), and the like; ASICs such as structured ASICs and the like; programmable SoCs (PSoCs); and the like. In such implementations, the circuitry of application circuitry 705 may comprise logic blocks or logic fabric, and other interconnected resources that may be programmed to perform various functions, such as the procedures, methods, functions, etc. of the various embodiments discussed herein. In such embodiments, the circuitry of application circuitry 705 may include memory cells (e.g., erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, static memory (e.g., static random access memory (SRAM), anti-fuses, etc.)) used to store logic blocks, logic fabric, data, etc. in look-up-tables (LUTs) and the like.

The baseband circuitry 710 may be implemented, for example, as a solder-down substrate including one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board or a multi-chip module containing two or more integrated circuits.

User interface circuitry 750 may include one or more user interfaces designed to enable user interaction with the system 700 or peripheral component interfaces designed to enable peripheral component interaction with the system 700. User interfaces may include, but are not limited to, one or more physical or virtual buttons (e.g., a reset button), one or more indicators (e.g., light emitting diodes (LEDs)), a physical keyboard or keypad, a mouse, a touchpad, a touchscreen, speakers or other audio emitting devices, microphones, a printer, a scanner, a headset, a display screen or display device, etc. Peripheral component interfaces may include, but are not limited to, a nonvolatile memory port, a universal serial bus (USB) port, an audio jack, a power supply interface, etc.

The radio front end modules (RFEMs) 715 may comprise a millimeter wave (mmWave) RFEM and one or more sub-mmWave radio frequency integrated circuits (RFICs). In some implementations, the one or more sub-mmWave RFICs may be physically separated from the mmWave RFEM. The RFICs may include connections to one or more antennas or antenna arrays, and the RFEM may be connected to multiple antennas. In alternative implementations, both mmWave and sub-mmWave radio functions may be implemented in the same physical RFEM 715, which incorporates both mmWave antennas and sub-mmWave.

The memory circuitry 720 may include one or more of volatile memory including dynamic random access memory (DRAM) and/or synchronous dynamic random access memory (SDRAM), and nonvolatile memory (NVM) including high-speed electrically erasable memory (commonly referred to as Flash memory), phase change random access memory (PRAM), magnetoresistive random access memory (MRAM), etc., and may incorporate the three-dimensional (3D) cross-point (XPOINT) memories from Intel® and Micron®. Memory circuitry 720 may be implemented as one or more of solder down packaged integrated circuits, socketed memory modules and plug-in memory cards.

The PMIC 725 may include voltage regulators, surge protectors, power alarm detection circuitry, and one or more backup power sources such as a battery or capacitor. The power alarm detection circuitry may detect one or more of brown out (under-voltage) and surge (over-voltage) conditions. The power tee circuitry 730 may provide for electrical power drawn from a network cable to provide both power supply and data connectivity to the infrastructure equipment 700 using a single cable.

The network controller circuitry 735 may provide connectivity to a network using a standard network interface protocol such as Ethernet, Ethernet over GRE Tunnels, Ethernet over Multiprotocol Label Switching (MPLS), or some other suitable protocol. Network connectivity may be provided to/from the infrastructure equipment 700 via network interface connector 740 using a physical connection, which may be electrical (commonly referred to as a “copper interconnect”), optical, or wireless. The network controller circuitry 735 may include one or more dedicated processors and/or FPGAs to communicate using one or more of the aforementioned protocols. In some implementations, the network controller circuitry 735 may include multiple controllers to provide connectivity to other networks using the same or different protocols.

The positioning circuitry 745 includes circuitry to receive and decode signals transmitted/broadcasted by a positioning network of a global navigation satellite system (GNSS). Examples of navigation satellite constellations (or GNSS) include United States' Global Positioning System (GPS), Russia's Global Navigation System (GLONASS), the European Union's Galileo system, China's BeiDou Navigation Satellite System, a regional navigation system or GNSS augmentation system (e.g., Navigation with Indian Constellation (NAVIC), Japan's Quasi-Zenith Satellite System (QZSS), France's Doppler Orbitography and Radio-positioning Integrated by Satellite (DORIS), etc.), or the like. The positioning circuitry 745 comprises various hardware elements (e.g., including hardware devices such as switches, filters, amplifiers, antenna elements, and the like to facilitate OTA communications) to communicate with components of a positioning network, such as navigation satellite constellation nodes. In some embodiments, the positioning circuitry 745 may include a Micro-Technology for Positioning, Navigation, and Timing (Micro-PNT) IC that uses a master timing clock to perform position tracking/estimation without GNSS assistance. The positioning circuitry 745 may also be part of, or interact with, the baseband circuitry 710 and/or RFEMs 715 to communicate with the nodes and components of the positioning network. The positioning circuitry 745 may also provide position data and/or time data to the application circuitry 705, which may use the data to synchronize operations with various infrastructure (e.g., RAN nodes 411, etc.), or the like.

The components shown by FIG. 7 may communicate with one another using interface circuitry, which may include any number of bus and/or interconnect (IX) technologies such as industry standard architecture (ISA), extended ISA (EISA), peripheral component interconnect (PCI), peripheral component interconnect extended (PCIx), PCI express (PCIe), or any number of other technologies. The bus/IX may be a proprietary bus, for example, used in a SoC based system. Other bus/IX systems may be included, such as an I2C interface, an SPI interface, point to point interfaces, and a power bus, among others.

FIG. 8 illustrates an example of a platform 800 (or “device 800”) in accordance with various embodiments. In embodiments, the computer platform 800 may be suitable for use as UEs 401, 501, 601, application servers 430, and/or any other element/device discussed herein. The platform 800 may include any combinations of the components shown in the example. The components of platform 800 may be implemented as integrated circuits (ICs), portions thereof, discrete electronic devices, or other modules, logic, hardware, software, firmware, or a combination thereof adapted in the computer platform 800, or as components otherwise incorporated within a chassis of a larger system. The block diagram of FIG. 8 is intended to show a high level view of components of the computer platform 800. However, some of the components shown may be omitted, additional components may be present, and different arrangement of the components shown may occur in other implementations.

Application circuitry 805 includes circuitry such as, but not limited to one or more processors (or processor cores), cache memory, and one or more of LDOs, interrupt controllers, serial interfaces such as SPI, I2C or universal programmable serial interface module, RTC, timer-counters including interval and watchdog timers, general purpose I/O, memory card controllers such as SD MMC or similar, USB interfaces, MIPI interfaces, and JTAG test access ports. The processors (or cores) of the application circuitry 805 may be coupled with or may include memory/storage elements and may be configured to execute instructions stored in the memory/storage to enable various applications or operating systems to run on the system 800. In some implementations, the memory/storage elements may be on-chip memory circuitry, which may include any suitable volatile and/or non-volatile memory, such as DRAM, SRAM, EPROM, EEPROM, Flash memory, solid-state memory, and/or any other type of memory device technology, such as those discussed herein.

The processor(s) of application circuitry 705 may include, for example, one or more processor cores, one or more application processors, one or more GPUs, one or more RISC processors, one or more ARM processors, one or more CISC processors, one or more DSP, one or more FPGAs, one or more PLDs, one or more ASICs, one or more microprocessors or controllers, a multithreaded processor, an ultra-low voltage processor, an embedded processor, some other known processing element, or any suitable combination thereof. In some embodiments, the application circuitry 705 may comprise, or may be, a special-purpose processor/controller to operate according to the various embodiments herein.

As examples, the processor(s) of application circuitry 805 may include an Apple A-series processor. The processors of the application circuitry 805 may also be one or more of Intel® Architecture Core™ based processor, such as a Quark™, an Atom™, an i3, an i5, an i7, or an MCU-class processor, or another such processor available from Intel® Corporation, Santa Clara, Calif.; Advanced Micro Devices (AMD) Ryzen® processor(s) or Accelerated Processing Units (APUs); Snapdragon™ processor(s) from Qualcomm® Technologies, Inc., Texas Instruments, Inc.® Open Multimedia Applications Platform (OMAP)™ processor(s); a MIPS-based design from MIPS Technologies, Inc. such as MIPS Warrior M-class, Warrior I-class, and Warrior P-class processors; an ARM-based design licensed from ARM Holdings, Ltd., such as the ARM Cortex-A, Cortex-R, and Cortex-M family of processors; or the like. In some implementations, the application circuitry 805 may be a part of a system on a chip (SoC) in which the application circuitry 805 and other components are formed into a single integrated circuit.

Additionally or alternatively, application circuitry 805 may include circuitry such as, but not limited to, one or more a field-programmable devices (FPDs) such as FPGAs and the like; programmable logic devices (PLDs) such as complex PLDs (CPLDs), high-capacity PLDs (HCPLDs), and the like; ASICs such as structured ASICs and the like; programmable SoCs (PSoCs); and the like. In such embodiments, the circuitry of application circuitry 805 may comprise logic blocks or logic fabric, and other interconnected resources that may be programmed to perform various functions, such as the procedures, methods, functions, etc. of the various embodiments discussed herein. In such embodiments, the circuitry of application circuitry 805 may include memory cells (e.g., erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, static memory (e.g., static random access memory (SRAM), anti-fuses, etc.)) used to store logic blocks, logic fabric, data, etc. in look-up tables (LUTs) and the like.

The baseband circuitry 810 may be implemented, for example, as a solder-down substrate including one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board or a multi-chip module containing two or more integrated circuits.

The RFEMs 815 may comprise a millimeter wave (mmWave) RFEM and one or more sub-mmWave radio frequency integrated circuits (RFICs). In some implementations, the one or more sub-mmWave RFICs may be physically separated from the mmWave RFEM. The RFICs may include connections to one or more antennas or antenna arrays, and the RFEM may be connected to multiple antennas. In alternative implementations, both mmWave and sub-mmWave radio functions may be implemented in the same physical RFEM 815, which incorporates both mmWave antennas and sub-mmWave.

The memory circuitry 820 may include any number and type of memory devices used to provide for a given amount of system memory. As examples, the memory circuitry 820 may include one or more of volatile memory including random access memory (RAM), dynamic RAM (DRAM) and/or synchronous dynamic RAM (SDRAM), and nonvolatile memory (NVM) including high-speed electrically erasable memory (commonly referred to as Flash memory), phase change random access memory (PRAM), magnetoresistive random access memory (MRAM), etc. The memory circuitry 820 may be developed in accordance with a Joint Electron Devices Engineering Council (JEDEC) low power double data rate (LPDDR)-based design, such as LPDDR2, LPDDR3, LPDDR4, or the like. Memory circuitry 820 may be implemented as one or more of solder down packaged integrated circuits, single die package (SDP), dual die package (DDP) or quad die package (Q17P), socketed memory modules, dual inline memory modules (DIMMs) including microDIMMs or MiniDIMMs, and/or soldered onto a motherboard via a ball grid array (BGA). In low power implementations, the memory circuitry 820 may be on-die memory or registers associated with the application circuitry 805. To provide for persistent storage of information such as data, applications, operating systems and so forth, memory circuitry 820 may include one or more mass storage devices, which may include, inter alia, a solid state disk drive (SSDD), hard disk drive (HDD), a micro HDD, resistance change memories, phase change memories, holographic memories, or chemical memories, among others. For example, the computer platform 800 may incorporate the three-dimensional (3D) cross-point (XPOINT) memories from Intel® and Micron®.

Removable memory circuitry 823 may include devices, circuitry, enclosures/housings, ports or receptacles, etc. used to couple portable data storage devices with the platform 800. These portable data storage devices may be used for mass storage purposes, and may include, for example, flash memory cards (e.g., Secure Digital (SD) cards, microSD cards, xD picture cards, and the like), and USB flash drives, optical discs, external HDDs, and the like.

The platform 800 may also include interface circuitry (not shown) that is used to connect external devices with the platform 800. The external devices connected to the platform 800 via the interface circuitry include sensor circuitry 821 and electro-mechanical components (EMCs) 822, as well as removable memory devices coupled to removable memory circuitry 823.

The sensor circuitry 821 include devices, modules, or subsystems whose purpose is to detect events or changes in its environment and send the information (sensor data) about the detected events to some other a device, module, subsystem, etc. Examples of such sensors include, inter alia, inertia measurement units (IMUs) comprising accelerometers, gyroscopes, and/or magnetometers; microelectromechanical systems (MEMS) or nanoelectromechanical systems (NEMS) comprising 3-axis accelerometers, 3-axis gyroscopes, and/or magnetometers; level sensors; flow sensors; temperature sensors (e.g., thermistors); pressure sensors; barometric pressure sensors; gravimeters; altimeters; image capture devices (e.g., cameras or lensless apertures); light detection and ranging (LiDAR) sensors; proximity sensors (e.g., infrared radiation detector and the like), depth sensors, ambient light sensors, ultrasonic transceivers; microphones or other like audio capture devices; etc.

EMCs 822 include devices, modules, or subsystems whose purpose is to enable platform 800 to change its state, position, and/or orientation, or move or control a mechanism or (sub)system. Additionally, EMCs 822 may be configured to generate and send messages/signaling to other components of the platform 800 to indicate a current state of the EMCs 822. Examples of the EMCs 822 include one or more power switches, relays including electromechanical relays (EMRs) and/or solid state relays (SSRs), actuators (e.g., valve actuators, etc.), an audible sound generator, a visual warning device, motors (e.g., DC motors, stepper motors, etc.), wheels, thrusters, propellers, claws, clamps, hooks, and/or other like electro-mechanical components. In embodiments, platform 800 is configured to operate one or more EMCs 822 based on one or more captured events and/or instructions or control signals received from a service provider and/or various clients.

In some implementations, the interface circuitry may connect the platform 800 with positioning circuitry 845. The positioning circuitry 845 includes circuitry to receive and decode signals transmitted/broadcasted by a positioning network of a GNSS. Examples of navigation satellite constellations (or GNSS) include United States' GPS, Russia's GLONASS, the European Union's Galileo system, China's BeiDou Navigation Satellite System, a regional navigation system or GNSS augmentation system (e.g., NAVIC), Japan's QZSS, France's DORIS, etc.), or the like. The positioning circuitry 845 comprises various hardware elements (e.g., including hardware devices such as switches, filters, amplifiers, antenna elements, and the like to facilitate OTA communications) to communicate with components of a positioning network, such as navigation satellite constellation nodes. In some embodiments, the positioning circuitry 845 may include a Micro-PNT IC that uses a master timing clock to perform position tracking/estimation without GNSS assistance. The positioning circuitry 845 may also be part of, or interact with, the baseband circuitry 710 and/or RFEMs 815 to communicate with the nodes and components of the positioning network. The positioning circuitry 845 may also provide position data and/or time data to the application circuitry 805, which may use the data to synchronize operations with various infrastructure (e.g., radio base stations), for turn-by-turn navigation applications, or the like

In some implementations, the interface circuitry may connect the platform 800 with Near-Field Communication (NFC) circuitry 840. NFC circuitry 840 is configured to provide contactless, short-range communications based on radio frequency identification (RFID) standards, wherein magnetic field induction is used to enable communication between NFC circuitry 840 and NFC-enabled devices external to the platform 800 (e.g., an “NFC touchpoint”). NFC circuitry 840 comprises an NFC controller coupled with an antenna element and a processor coupled with the NFC controller. The NFC controller may be a chip/IC providing NFC functionalities to the NFC circuitry 840 by executing NFC controller firmware and an NFC stack. The NFC stack may be executed by the processor to control the NFC controller, and the NFC controller firmware may be executed by the NFC controller to control the antenna element to emit short-range RF signals. The RF signals may power a passive NFC tag (e.g., a microchip embedded in a sticker or wristband) to transmit stored data to the NFC circuitry 840, or initiate data transfer between the NFC circuitry 840 and another active NFC device (e.g., a smartphone or an NFC-enabled POS terminal) that is proximate to the platform 800.

The driver circuitry 846 may include software and hardware elements that operate to control particular devices that are embedded in the platform 800, attached to the platform 800, or otherwise communicatively coupled with the platform 800. The driver circuitry 846 may include individual drivers allowing other components of the platform 800 to interact with or control various input/output (I/O) devices that may be present within, or connected to, the platform 800. For example, driver circuitry 846 may include a display driver to control and allow access to a display device, a touchscreen driver to control and allow access to a touchscreen interface of the platform 800, sensor drivers to obtain sensor readings of sensor circuitry 821 and control and allow access to sensor circuitry 821, EMC drivers to obtain actuator positions of the EMCs 822 and/or control and allow access to the EMCs 822, a camera driver to control and allow access to an embedded image capture device, audio drivers to control and allow access to one or more audio devices.

The power management integrated circuitry (PMIC) 825 (also referred to as “power management circuitry 825”) may manage power provided to various components of the platform 800. In particular, with respect to the baseband circuitry 810, the PMIC 825 may control power-source selection, voltage scaling, battery charging, or DC-to-DC conversion. The PMIC 825 may often be included when the platform 800 is capable of being powered by a battery 830, for example, when the device is included in a UE 401, 501, 601.

In some embodiments, the PMIC 825 may control, or otherwise be part of, various power saving mechanisms of the platform 800. For example, if the platform 800 is in an RRC_Connected state, where it is still connected to the RAN node as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity. During this state, the platform 800 may power down for brief intervals of time and thus save power. If there is no data traffic activity for an extended period of time, then the platform 800 may transition off to an RRC_Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The platform 800 goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. The platform 800 may not receive data in this state; in order to receive data, it must transition back to RRC_Connected state. An additional power saving mode may allow a device to be unavailable to the network for periods longer than a paging interval (ranging from seconds to a few hours). During this time, the device is totally unreachable to the network and may power down completely. Any data sent during this time incurs a large delay and it is assumed the delay is acceptable.

A battery 830 may power the platform 800, although in some examples the platform 800 may be mounted deployed in a fixed location, and may have a power supply coupled to an electrical grid. The battery 830 may be a lithium ion battery, a metal-air battery, such as a zinc-air battery, an aluminum-air battery, a lithium-air battery, and the like. In some implementations, such as in V2X applications, the battery 830 may be a typical lead-acid automotive battery.

In some implementations, the battery 830 may be a “smart battery,” which includes or is coupled with a Battery Management System (BMS) or battery monitoring integrated circuitry. The BMS may be included in the platform 800 to track the state of charge (SoCh) of the battery 830. The BMS may be used to monitor other parameters of the battery 830 to provide failure predictions, such as the state of health (SoH) and the state of function (SoF) of the battery 830. The BMS may communicate the information of the battery 830 to the application circuitry 805 or other components of the platform 800. The BMS may also include an analog-to-digital (ADC) convertor that allows the application circuitry 805 to directly monitor the voltage of the battery 830 or the current flow from the battery 830. The battery parameters may be used to determine actions that the platform 800 may perform, such as transmission frequency, network operation, sensing frequency, and the like.

A power block, or other power supply coupled to an electrical grid may be coupled with the BMS to charge the battery 830. In some examples, the power block XS30 may be replaced with a wireless power receiver to obtain the power wirelessly, for example, through a loop antenna in the computer platform 800. In these examples, a wireless battery charging circuit may be included in the BMS. The specific charging circuits chosen may depend on the size of the battery 830, and thus, the current required. The charging may be performed using the Airfuel standard promulgated by the Airfuel Alliance, the Qi wireless charging standard promulgated by the Wireless Power Consortium, or the Rezence charging standard promulgated by the Alliance for Wireless Power, among others.

User interface circuitry 850 includes various input/output (I/O) devices present within, or connected to, the platform 800, and includes one or more user interfaces designed to enable user interaction with the platform 800 and/or peripheral component interfaces designed to enable peripheral component interaction with the platform 800. The user interface circuitry 850 includes input device circuitry and output device circuitry. Input device circuitry includes any physical or virtual means for accepting an input including, inter alia, one or more physical or virtual buttons (e.g., a reset button), a physical keyboard, keypad, mouse, touchpad, touchscreen, microphones, scanner, headset, and/or the like. The output device circuitry includes any physical or virtual means for showing information or otherwise conveying information, such as sensor readings, actuator position(s), or other like information. Output device circuitry may include any number and/or combinations of audio or visual display, including, inter alia, one or more simple visual outputs/indicators (e.g., binary status indicators (e.g., light emitting diodes (LEDs)) and multi-character visual outputs, or more complex outputs such as display devices or touchscreens (e.g., Liquid Chrystal Displays (LCD), LED displays, quantum dot displays, projectors, etc.), with the output of characters, graphics, multimedia objects, and the like being generated or produced from the operation of the platform 800. The output device circuitry may also include speakers or other audio emitting devices, printer(s), and/or the like. In some embodiments, the sensor circuitry 821 may be used as the input device circuitry (e.g., an image capture device, motion capture device, or the like) and one or more EMCs may be used as the output device circuitry (e.g., an actuator to provide haptic feedback or the like). In another example, NFC circuitry comprising an NFC controller coupled with an antenna element and a processing device may be included to read electronic tags and/or connect with another NFC-enabled device. Peripheral component interfaces may include, but are not limited to, a non-volatile memory port, a USB port, an audio jack, a power supply interface, etc.

Although not shown, the components of platform 800 may communicate with one another using a suitable bus or interconnect (IX) technology, which may include any number of technologies, including ISA, EISA, PCI, PCIx, PCIe, a Time-Trigger Protocol (TTP) system, a FlexRay system, or any number of other technologies. The bus/IX may be a proprietary bus/IX, for example, used in a SoC based system. Other bus/IX systems may be included, such as an I2C interface, an SPI interface, point-to-point interfaces, and a power bus, among others.

FIG. 9 illustrates various protocol functions that may be implemented in a wireless communication device according to various embodiments. In particular, FIG. 9 includes an arrangement 900 showing interconnections between various protocol layers/entities. The following description of FIG. 9 is provided for various protocol layers/entities that operate in conjunction with the 5G/NR system standards and LTE system standards, but some or all of the aspects of FIG. 9 may be applicable to other wireless communication network systems as well.

The protocol layers of arrangement 900 may include one or more of PHY 910, MAC 920, RLC 930, PDCP 940, SDAP 947, RRC 955, and NAS layer 957, in addition to other higher layer functions not illustrated. The protocol layers may include one or more service access points (e.g., items 959, 956, 950, 949, 945, 935, 925, and 915 in FIG. 9) that may provide communication between two or more protocol layers.

The PHY 910 may transmit and receive physical layer signals 905 that may be received from or transmitted to one or more other communication devices. The physical layer signals 905 may comprise one or more physical channels, such as those discussed herein. The PHY 910 may further perform link adaptation or adaptive modulation and coding (AMC), power control, cell search (e.g., for initial synchronization and handover purposes), and other measurements used by higher layers, such as the RRC 955. The PHY 910 may still further perform error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, modulation/demodulation of physical channels, interleaving, rate matching, mapping onto physical channels, and MIMO antenna processing. In embodiments, an instance of PHY 910 may process requests from and provide indications to an instance of MAC 920 via one or more PHY-SAP 915. According to some embodiments, requests and indications communicated via PHY-SAP 915 may comprise one or more transport channels.

Instance(s) of MAC 920 may process requests from, and provide indications to, an instance of RLC 930 via one or more MAC-SAPs 925. These requests and indications communicated via the MAC-SAP 925 may comprise one or more logical channels. The MAC 920 may perform mapping between the logical channels and transport channels, multiplexing of MAC SDUs from one or more logical channels onto TBs to be delivered to PHY 910 via the transport channels, de-multiplexing MAC SDUs to one or more logical channels from TBs delivered from the PHY 910 via transport channels, multiplexing MAC SDUs onto TBs, scheduling information reporting, error correction through HARQ, and logical channel prioritization.

Instance(s) of RLC 930 may process requests from and provide indications to an instance of PDCP 940 via one or more radio link control service access points (RLC-SAP) 935. These requests and indications communicated via RLC-SAP 935 may comprise one or more RLC channels. The RLC 930 may operate in a plurality of modes of operation, including: Transparent Mode™, Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC 930 may execute transfer of upper layer protocol data units (PDUs), error correction through automatic repeat request (ARQ) for AM data transfers, and concatenation, segmentation and reassembly of RLC SDUs for UM and AM data transfers. The RLC 930 may also execute re-segmentation of RLC data PDUs for AM data transfers, reorder RLC data PDUs for UM and AM data transfers, detect duplicate data for UM and AM data transfers, discard RLC SDUs for UM and AM data transfers, detect protocol errors for AM data transfers, and perform RLC re-establishment.

Instance(s) of PDCP 940 may process requests from and provide indications to instance(s) of RRC 955 and/or instance(s) of SDAP 947 via one or more packet data convergence protocol service access points (PDCP-SAP) 945. These requests and indications communicated via PDCP-SAP 945 may comprise one or more radio bearers. The PDCP 940 may execute header compression and decompression of IP data, maintain PDCP Sequence Numbers (SNs), perform in-sequence delivery of upper layer PDUs at re-establishment of lower layers, eliminate duplicates of lower layer SDUs at re-establishment of lower layers for radio bearers mapped on RLC AM, cipher and decipher control plane data, perform integrity protection and integrity verification of control plane data, control timer-based discard of data, and perform security operations (e.g., ciphering, deciphering, integrity protection, integrity verification, etc.).

Instance(s) of SDAP 947 may process requests from and provide indications to one or more higher layer protocol entities via one or more SDAP-SAP 949. These requests and indications communicated via SDAP-SAP 949 may comprise one or more QoS flows. The SDAP 947 may map QoS flows to DRBs, and vice versa, and may also mark QFIs in DL and UL packets. A single SDAP entity 947 may be configured for an individual PDU session. In the UL direction, the NG-RAN 410 may control the mapping of QoS Flows to DRB(s) in two different ways, reflective mapping or explicit mapping. For reflective mapping, the SDAP 947 of a UE 401 may monitor the QFIs of the DL packets for each DRB, and may apply the same mapping for packets flowing in the UL direction. For a DRB, the SDAP 947 of the UE 401 may map the UL packets belonging to the QoS flows(s) corresponding to the QoS flow ID(s) and PDU session observed in the DL packets for that DRB. To enable reflective mapping, the NG-RAN 610 may mark DL packets over the Uu interface with a QoS flow ID. The explicit mapping may involve the RRC 955 configuring the SDAP 947 with an explicit QoS flow to DRB mapping rule, which may be stored and followed by the SDAP 947. In embodiments, the SDAP 947 may only be used in NR implementations and may not be used in LTE implementations.

The RRC 955 may configure, via one or more management service access points (M-SAP), aspects of one or more protocol layers, which may include one or more instances of PHY 910, MAC 920, RLC 930, PDCP 940 and SDAP 947. In embodiments, an instance of RRC 955 may process requests from and provide indications to one or more NAS entities 957 via one or more RRC-SAPs 956. The main services and functions of the RRC 955 may include broadcast of system information (e.g., included in MIBs or SIBs related to the NAS), broadcast of system information related to the access stratum (AS), paging, establishment, maintenance and release of an RRC connection between the UE 401 and RAN 410 (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), establishment, configuration, maintenance and release of point to point Radio Bearers, security functions including key management, inter-RAT mobility, and measurement configuration for UE measurement reporting. The MIBs and SIBs may comprise one or more IEs, which may each comprise individual data fields or data structures.

The NAS 957 may form the highest stratum of the control plane between the UE 401 and the AMF 621. The NAS 957 may support the mobility of the UEs 401 and the session management procedures to establish and maintain IP connectivity between the UE 401 and a P-GW in LTE systems.

According to various embodiments, one or more protocol entities of arrangement 900 may be implemented in UEs 401, RAN nodes 411, AMF 621 in NR implementations or MME 521 in LTE implementations, UPF 602 in NR implementations or S-GW 522 and P-GW 523 in LTE implementations, or the like to be used for control plane or user plane communications protocol stack between the aforementioned devices. In such embodiments, one or more protocol entities that may be implemented in one or more of UE 401, gNB 411, AMF 621, etc. may communicate with a respective peer protocol entity that may be implemented in or on another device using the services of respective lower layer protocol entities to perform such communication. In some embodiments, a gNB-CU of the gNB 411 may host the RRC 955, SDAP 947, and PDCP 940 of the gNB that controls the operation of one or more gNB-DUs, and the gNB-DUs of the gNB 411 may each host the RLC 930, MAC 920, and PHY 910 of the gNB 411.

In a first example, a control plane protocol stack may comprise, in order from highest layer to lowest layer, NAS 957, RRC 955, PDCP 940, RLC 930, MAC 920, and PHY 910. In this example, upper layers 960 may be built on top of the NAS 957, which includes an IP layer 961, an SCTP 962, and an application layer signaling protocol (AP) 963.

In NR implementations, the AP 963 may be an NG application protocol layer (NGAP or NG-AP) 963 for the NG interface 413 defined between the NG-RAN node 411 and the AMF 621, or the AP 963 may be an Xn application protocol layer (XnAP or Xn-AP) 963 for the Xn interface 412 that is defined between two or more RAN nodes 411.

The NG-AP 963 may support the functions of the NG interface 413 and may comprise Elementary Procedures (EPs). An NG-AP EP may be a unit of interaction between the NG-RAN node 411 and the AMF 621. The NG-AP 963 services may comprise two groups: UE-associated services (e.g., services related to a UE 401) and non-UE-associated services (e.g., services related to the whole NG interface instance between the NG-RAN node 411 and AMF 621). These services may include functions including, but not limited to: a paging function for the sending of paging requests to NG-RAN nodes 411 involved in a particular paging area; a UE context management function for allowing the AMF 621 to establish, modify, and/or release a UE context in the AMF 621 and the NG-RAN node 411, a mobility function for UEs 401 in ECM-CONNECTED mode for intra-system HOs to support mobility within NG-RAN and inter-system HOs to support mobility from/to EPS systems; a NAS Signaling Transport function for transporting or rerouting NAS messages between UE 401 and AMF 621; a NAS node selection function for determining an association between the AMF 621 and the UE 401; NG interface management function(s) for setting up the NG interface and monitoring for errors over the NG interface; a warning message transmission function for providing means to transfer warning messages via NG interface or cancel ongoing broadcast of warning messages; a Configuration Transfer function for requesting and transferring of RAN configuration information (e.g., SON information, performance measurement (PM) data, etc.) between two RAN nodes 411 via CN 420; and/or other like functions.

The XnAP 963 may support the functions of the Xn interface 412 and may comprise XnAP basic mobility procedures and XnAP global procedures. The XnAP basic mobility procedures may comprise procedures used to handle UE mobility within the NG RAN 411 (or E-UTRAN 510), such as handover preparation and cancellation procedures, SN Status Transfer procedures, UE context retrieval and UE context release procedures, RAN paging procedures, dual connectivity related procedures, and the like. The XnAP global procedures may comprise procedures that are not related to a specific UE 401, such as Xn interface setup and reset procedures, NG-RAN update procedures, cell activation procedures, and the like.

In LTE implementations, the AP 963 may be an S1 Application Protocol layer (SJ-AP) 963 for the S1 interface 413 defined between an E-UTRAN node 411 and an MME, or the AP 963 may be an X2 application protocol layer (X2AP or X2-AP) 963 for the X2 interface 412 that is defined between two or more E-UTRAN nodes 411.

The S1 Application Protocol layer (S1-AP) 963 may support the functions of the S1 interface, and similar to the NG-AP discussed previously, the S1-AP may comprise S1-AP EPs. An S1-AP EP may be a unit of interaction between the E-UTRAN node 411 and an MME 521 within an LTE CN 420. The S1-AP 963 services may comprise two groups: UE-associated services and non UE-associated services. These services perform functions including, but not limited to: E-UTRAN Radio Access Bearer (E-RAB) management, UE capability indication, mobility, NAS signaling transport, RAN Information Management (RIM), and configuration transfer.

The X2AP 963 may support the functions of the X2 interface 412 and may comprise X2AP basic mobility procedures and X2AP global procedures. The X2AP basic mobility procedures may comprise procedures used to handle UE mobility within the E-UTRAN 420, such as handover preparation and cancellation procedures, SN Status Transfer procedures, UE context retrieval and UE context release procedures, RAN paging procedures, dual connectivity related procedures, and the like. The X2AP global procedures may comprise procedures that are not related to a specific UE 401, such as X2 interface setup and reset procedures, load indication procedures, error indication procedures, cell activation procedures, and the like.

The SCTP layer (alternatively referred to as the SCTP/IP layer) 962 may provide guaranteed delivery of application layer messages (e.g., NGAP or XnAP messages in NR implementations, or S1-AP or X2AP messages in LTE implementations). The SCTP 962 may ensure reliable delivery of signaling messages between the RAN node 411 and the AMF 621/MME 521 based, in part, on the IP protocol, supported by the IP 961. The Internet Protocol layer (IP) 961 may be used to perform packet addressing and routing functionality. In some implementations the IP layer 961 may use point-to-point transmission to deliver and convey PDUs. In this regard, the RAN node 411 may comprise L2 and L1 layer communication links (e.g., wired or wireless) with the MME/AMF to exchange information.

In a second example, a user plane protocol stack may comprise, in order from highest layer to lowest layer, SDAP 947, PDCP 940, RLC 930, MAC 920, and PHY 910. The user plane protocol stack may be used for communication between the UE 401, the RAN node 411, and UPF 602 in NR implementations or an S-GW 522 and P-GW 523 in LTE implementations. In this example, upper layers 951 may be built on top of the SDAP 947, and may include a user datagram protocol (UDP) and IP security layer (UDP/IP) 952, a General Packet Radio Service (GPRS) Tunneling Protocol for the user plane layer (GTP-U) 953, and a User Plane PDU layer (UP PDU) 963.

The transport network layer 954 (also referred to as a “transport layer”) may be built on IP transport, and the GTP-U 953 may be used on top of the UDP/IP layer 952 (comprising a UDP layer and IP layer) to carry user plane PDUs (UP-PDUs). The IP layer (also referred to as the “Internet layer”) may be used to perform packet addressing and routing functionality. The IP layer may assign IP addresses to user data packets in any of IPv4, IPv6, or PPP formats, for example.

The GTP-U 953 may be used for carrying user data within the GPRS core network and between the radio access network and the core network. The user data transported can be packets in any of IPv4, IPv6, or PPP formats, for example. The UDP/IP 952 may provide checksums for data integrity, port numbers for addressing different functions at the source and destination, and encryption and authentication on the selected data flows. The RAN node 411 and the S-GW 522 may utilize an S1-U interface to exchange user plane data via a protocol stack comprising an L1 layer (e.g., PHY 910), an L2 layer (e.g., MAC 920, RLC 930, PDCP 940, and/or SDAP 947), the UDP/IP layer 952, and the GTP-U 953. The S-GW 522 and the P-GW 523 may utilize an S5/S8a interface to exchange user plane data via a protocol stack comprising an L1 layer, an L2 layer, the UDP/IP layer 952, and the GTP-U 953. As discussed previously, NAS protocols may support the mobility of the UE 401 and the session management procedures to establish and maintain IP connectivity between the UE 401 and the P-GW 523.

Moreover, although not shown by FIG. 9, an application layer may be present above the AP 963 and/or the transport network layer 954. The application layer may be a layer in which a user of the UE 401, RAN node 411, or other network element interacts with software applications being executed, for example, by application circuitry 705 or application circuitry 805, respectively. The application layer may also provide one or more interfaces for software applications to interact with communications systems of the UE 401 or RAN node 411, such as the baseband circuitry XT110. In some implementations the IP layer and/or the application layer may provide the same or similar functionality as layers 5-7, or portions thereof, of the Open Systems Interconnection (OSI) model (e.g., OSI Layer 7—the application layer, OSI Layer 6—the presentation layer, and OSI Layer 5—the session layer).

FIG. 10 is a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein. Specifically, FIG. 10 shows a diagrammatic representation of hardware resources 1000 including one or more processors (or processor cores) 1010, one or more memory/storage devices 1020, and one or more communication resources 1030, each of which may be communicatively coupled via a bus 1040. For embodiments where node virtualization (e.g., NFV) is utilized, a hypervisor 1002 may be executed to provide an execution environment for one or more network slices/sub-slices to utilize the hardware resources 1000.

The processors 1010 may include, for example, a processor 1012 and a processor 1014. The processor(s) 1010 may be, for example, a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a DSP such as a baseband processor, an ASIC, an FPGA, a radio-frequency integrated circuit (RFIC), another processor (including those discussed herein), or any suitable combination thereof.

The memory/storage devices 1020 may include main memory, disk storage, or any suitable combination thereof. The memory/storage devices 1020 may include, but are not limited to, any type of volatile or nonvolatile memory such as dynamic random access memory (DRAM), static random access memory (SRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), Flash memory, solid-state storage, etc.

The communication resources 1030 may include interconnection or network interface components or other suitable devices to communicate with one or more peripheral devices 1004 or one or more databases 1006 via a network 1008. For example, the communication resources 1030 may include wired communication components (e.g., for coupling via USB), cellular communication components, NFC components, Bluetooth® (or Bluetooth® Low Energy) components, Wi-Fi® components, and other communication components.

Instructions 1050 may comprise software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors 1010 to perform any one or more of the methodologies discussed herein. The instructions 1050 may reside, completely or partially, within at least one of the processors 1010 (e.g., within the processor's cache memory), the memory/storage devices 1020, or any suitable combination thereof. Furthermore, any portion of the instructions 1050 may be transferred to the hardware resources 1000 from any combination of the peripheral devices 1004 or the databases 1006. Accordingly, the memory of processors 1010, the memory/storage devices 1020, the peripheral devices 1004, and the databases 1006 are examples of computer-readable and machine-readable media. 

1. In an integrated access and backhaul (IAB) system comprising an IAB node and an IAB donor, a method comprising: determining, by a distributed unit (DU) of the IAB node and based on a configuration signal received from a central unit (CU) of the IAB donor, a configuration of available soft resources for a child link of the IAB node; determining, based on the configuration of available soft resources, a start symbol of the available soft resources; and using the available soft resources for one or more child link transmissions starting from the start symbol.
 2. The method of claim 1, wherein the configuration of available soft resources is applied relative to slot timing of the DU.
 3. The method of claim 1, wherein the configuration of available soft resources is indicated by the configuration signal on a symbol level per transmission direction if downlink and uplink timings of the DU are configured differently.
 4. The method of claim 1, wherein the start symbol is based on at least one of: a transmission direction of a last used symbol in a parent link of the IAB node, a resource type or transmission direction of soft resources in the child link, a downlink propagation delay (T_(D)) of the parent link, an uplink timing advance (T_(A)) of the parent link, or a downlink/uplink timing difference (T_(D/U)) at the DU.
 5. The method of claim 4, wherein a transmission direction of the parent link is downlink when the IAB node receives a transmission from a parent IAB node, a transmission direction of the parent link is uplink when the IAB node sends a transmission to the parent IAB node, a transmission direction of the child link is downlink when the IAB node sends a transmission to a child node, and a transmission direction of the child link is uplink when the IAB node receives a transmission from the child node.
 6. The method of claim 1, wherein a transmission direction of a last used symbol in a parent link of the IAB node and the available soft resources is downlink, wherein the available soft resources overlap with the last used downlink symbol of the parent link, wherein the last used downlink symbol of the parent link is at symbol index n, and wherein the start symbol of the available soft resources is at symbol index n+2.
 7. The method of claim 1, wherein a transmission direction of a last used symbol in the parent link is downlink, wherein a transmission direction of the available soft resources is uplink, wherein the available soft resources overlap with the last used downlink symbol of the parent link, wherein a downlink/uplink timing difference (T_(D/U)) at the DU is greater than a downlink propagation delay (T_(D)) of the parent link, wherein the last used downlink symbol of the parent link is at symbol index n, and wherein the start symbol of the available soft resources is at symbol index n+1.
 8. The method of claim 1, wherein a transmission direction of a last used symbol in the parent link is downlink, wherein a transmission direction of the available soft resources is uplink, wherein the available soft resources overlap with the last used downlink symbol of the parent link, wherein a downlink/uplink timing difference (T_(D/U)) at the DU is less than a downlink propagation delay (T_(D)) of the parent link, wherein the last used downlink symbol of the parent link is at symbol index n, and wherein the start symbol of the available soft resources is at symbol index n+2.
 9. The method of claim 1, wherein a transmission direction of a last used symbol in the parent link is uplink, wherein a transmission direction of the available soft resources is downlink, wherein the available soft resources overlap with the uplink symbol of the parent link, wherein the last used downlink symbol of the parent link is at symbol index n, and wherein the start symbol of the available soft resources is at symbol index n+1.
 10. The method of claim 1, wherein a transmission direction of a last used symbol in the parent link and the available soft resources is uplink, wherein a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is less than a symbol duration, wherein the last used uplink symbol of the parent link is at symbol index n, and wherein the start symbol of the available soft resources is at symbol index n+1.
 11. The method of claim 1, wherein a transmission direction of a last used symbol in the parent link and the available soft resources is uplink, wherein a sum of a downlink/uplink timing difference (T_(D/U)) at the DU and uplink timing advance (T_(A)) of the parent link is greater than a symbol duration, wherein the last used uplink symbol of the parent link is at symbol index n, and wherein the start symbol of the available soft resources is at symbol index n.
 12. The method of claim 1, wherein the CU receives information indicative of guard symbols for the DU via an F1-AP interface message. 13-17. (canceled)
 18. In an integrated access and backhaul (IAB) system including an IAB node and an IAB donor, a non-transitory computer-readable storage device having stored thereon the instructions, which, when executed by a data processing apparatus, cause the data processing apparatus to perform operations comprising: determining, by the IAB node and based on a configuration signal received from the IAB donor, a configuration of available soft resources for a child link of the IAB node; and determining, based on the configuration of available soft resources, a start symbol of the available soft resources.
 19. (canceled)
 20. An integrated access and backhaul (IAB) system comprising: an IAB node comprising a distributed unit (DU) and a mobile termination (MT), wherein the IAB node has a parent link and a child link; an IAB donor comprising a central unit (CU); and one or more processors and one or more storage devices storing instructions that are operable, when executed by the one or more processors, to cause the one or more processors to perform operations comprising: determining, by the DU and based on a configuration signal received from the CU, a configuration of available soft resources for the child link; and determining, based on the configuration of available soft resources, a start symbol of the available soft resources.
 21. The non-transitory computer-readable storage device of claim 18 storing instructions which, when executed by the data processing apparatus, cause the data processing apparatus to perform operations comprising: using the available soft resources for one or more child link transmissions starting from the start symbol.
 22. The non-transitory computer-readable storage device of claim 18, wherein the configuration of available soft resources is applied relative to slot timing of the IAB node.
 23. The non-transitory computer-readable storage device of claim 18, wherein the configuration of available soft resources is indicated by the configuration signal on a symbol level per transmission direction if downlink and uplink timings of the IAB node are configured differently.
 24. The system of claim 20, wherein the one or more storage devices store instructions that are operable, when executed by the one or more processors, to cause the one or more processors to perform operations comprising: using the available soft resources for one or more child link transmissions starting from the start symbol.
 25. The system of claim 20, wherein the configuration of available soft resources is applied relative to slot timing of the IAB node.
 26. The system of claim 20, wherein the configuration of available soft resources is indicated by the configuration signal on a symbol level per transmission direction if downlink and uplink timings of the IAB node are configured differently. 